bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2024‒05‒19
thirty-two papers selected by
Kıvanç Görgülü, Technical University of Munich
  1. AMPK as a mediator of tissue preservation: time for a shift in dogma?
  2. The Janus kinase 1 is critical for pancreatic cancer initiation and progression.
  3. Mammalian pexophagy at a glance.
  4. Receptor-mediated cargo hitchhiking on bulk autophagy.
  5. Multiparameter flow cytometric detection and analysis of rare cells in in vivo models of cancer metastasis.
  6. In vivo CRISPR screening identifies geranylgeranyl diphosphate as a pancreatic cancer tumor growth dependency.
  7. One-carbon unit supplementation fuels purine synthesis in tumor-infiltrating T cells and augments checkpoint blockade.
  8. The lactate wasteland.
  9. Aging and cancer.
  10. Exploiting the ferroaddiction of pancreatic cancer cells using Fe-doped nanoparticles.
  11. GATA6 identifies an immune-enriched phenotype linked to favorable outcomes in patients with pancreatic cancer undergoing upfront surgery.
  12. A delicate decision between repair and degradation of damaged lysosomes.
  13. Palmitoyl transferase ZDHHC20 promotes pancreatic cancer metastasis.
  14. Decoding the interplay between genetic and non-genetic drivers of metastasis.
  15. Expression of the membrane tetraspanin claudin 18 on cancer cells promotes T lymphocyte infiltration and antitumor immunity in pancreatic cancer.
  16. KRT81 and HNF1A expression in pancreatic ductal adenocarcinoma: investigation of predictive and prognostic value of immunohistochemistry-based subtyping.
  17. Autophagy preferentially degrades non-fibrillar polyQ aggregates.
  18. NEMO/NF-κB signaling functions as a double-edged sword in PanIN formation versus progression to pancreatic cancer.
  19. Methods for making and observing model lipid droplets.
  20. Methyl-β-cyclodextrin asymmetrically extracts phospholipid from bilayers, granting tunable control over differential stress in lipid vesicles.
  21. Genome-wide CRISPR screens in spheroid culture reveal that the tumor suppressor LKB1 inhibits growth via the PIKFYVE lipid kinase.
  22. High-throughput mechanical phenotyping and transcriptomics of single cells.
  23. "Tumor-selective treatment of metastatic pancreatic cancer with an engineered, probiotic living drug".
  24. Quantitative Measurement of Plasma Membrane Protein Internalisation and Recycling in Heterogenous Cellular Samples by Flow Cytometry.
  25. The roles of PD-L1 in the various stages of tumor metastasis.
  26. Membrane Tilt Drives Phase Separation of Adhesion Receptors.
  27. Making the cut: Multiscale simulation of membrane remodeling.
  28. The Peptidoglycan Recognition Protein 1 confers immune evasive properties on pancreatic cancer stem cells.
  29. Unraveling ETC complex I function in ferroptosis reveals a potential ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers.
  30. Measuring the Transmembrane Registration of Lipid Domains in Droplet Interface Bilayers through Tensiometry.
  31. Genetically predicted blood metabolites mediate the association between circulating immune cells and pancreatic cancer: A Mendelian randomization study.
  32. Impairing hydrolase transport machinery prevents human melanoma metastasis.
  1. Nat Rev Endocrinol. 2024 May 17.
    AMPK as a mediator of tissue preservation: time for a shift in dogma?
    Henning Tim Langer, Maria Rohm, Marcus DaSilva Goncalves, Lykke Sylow.
      Ground-breaking discoveries have established 5'-AMP-activated protein kinase (AMPK) as a central sensor of metabolic stress in cells and tissues. AMPK is activated through cellular starvation, exercise and drugs by either directly or indirectly affecting the intracellular AMP (or ADP) to ATP ratio. In turn, AMPK regulates multiple processes of cell metabolism, such as the maintenance of cellular ATP levels, via the regulation of fatty acid oxidation, glucose uptake, glycolysis, autophagy, mitochondrial biogenesis and degradation, and insulin sensitivity. Moreover, AMPK inhibits anabolic processes, such as lipogenesis and protein synthesis. These findings support the notion that AMPK is a crucial regulator of cell catabolism. However, studies have revealed that AMPK's role in cell homeostasis might not be as unidirectional as originally thought. This Review explores emerging evidence for AMPK as a promoter of cell survival and an enhancer of anabolic capacity in skeletal muscle and adipose tissue during catabolic crises. We discuss AMPK-activating interventions for tissue preservation during tissue wasting in cancer-associated cachexia and explore the clinical potential of AMPK activation in wasting conditions. Overall, we provide arguments that call for a shift in the current dogma of AMPK as a mere regulator of cell catabolism, concluding that AMPK has an unexpected role in tissue preservation.
    DOI:  https://doi.org/10.1038/s41574-024-00992-y
  2. Cell Rep. 2024 May 10. pii: S2211-1247(24)00530-8. [Epub ahead of print]43(5): 114202
    The Janus kinase 1 is critical for pancreatic cancer initiation and progression.
    Hridaya Shrestha, Patrick D Rädler, Rayane Dennaoui, Madison N Wicker, Nirakar Rajbhandari, Yunguang Sun, Amy R Peck, Kerry Vistisen, Aleata A Triplett, Rafic Beydoun, Esta Sterneck, Dieter Saur, Hallgeir Rui, Kay-Uwe Wagner.
      Interleukin-6 (IL-6)-class inflammatory cytokines signal through the Janus tyrosine kinase (JAK)/signal transducer and activator of transcription (STAT) pathway and promote the development of pancreatic ductal adenocarcinoma (PDAC); however, the functions of specific intracellular signaling mediators in this process are less well defined. Using a ligand-controlled and pancreas-specific knockout in adult mice, we demonstrate in this study that JAK1 deficiency prevents the formation of KRASG12D-induced pancreatic tumors, and we establish that JAK1 is essential for the constitutive activation of STAT3, whose activation is a prominent characteristic of PDAC. We identify CCAAT/enhancer binding protein δ (C/EBPδ) as a biologically relevant downstream target of JAK1 signaling, which is upregulated in human PDAC. Reinstating the expression of C/EBPδ was sufficient to restore the growth of JAK1-deficient cancer cells as tumorspheres and in xenografted mice. Collectively, the findings of this study suggest that JAK1 executes important functions of inflammatory cytokines through C/EBPδ and may serve as a molecular target for PDAC prevention and treatment.
    Keywords:  CEBPD; CP: Cancer; Janus kinase 1; PDAC; RNA sequencing; STAT proteins; gene targeting; humans; mice; pancreatic cancer; pancreatic neoplasms; phosphorylation; signal transduction; transcription factor; transgenic; tyrosine kinase
    DOI:  https://doi.org/10.1016/j.celrep.2024.114202
  3. J Cell Sci. 2024 May 01. pii: jcs259775. [Epub ahead of print]137(9):
    Mammalian pexophagy at a glance.
    Justyna Bajdzienko, Anja Bremm.
      Peroxisomes are highly plastic organelles that are involved in several metabolic processes, including fatty acid oxidation, ether lipid synthesis and redox homeostasis. Their abundance and activity are dynamically regulated in response to nutrient availability and cellular stress. Damaged or superfluous peroxisomes are removed mainly by pexophagy, the selective autophagy of peroxisomes induced by ubiquitylation of peroxisomal membrane proteins or ubiquitin-independent processes. Dysregulated pexophagy impairs peroxisome homeostasis and has been linked to the development of various human diseases. Despite many recent insights into mammalian pexophagy, our understanding of this process is still limited compared to our understanding of pexophagy in yeast. In this Cell Science at a Glance article and the accompanying poster, we summarize current knowledge on the control of mammalian pexophagy and highlight which aspects require further attention. We also discuss the role of ubiquitylation in pexophagy and describe the ubiquitin machinery involved in regulating signals for the recruitment of phagophores to peroxisomes.
    Keywords:  Peroxisome; Pexophagy; Selective autophagy; Ubiquitylation
    DOI:  https://doi.org/10.1242/jcs.259775
  4. EMBO J. 2024 May 16.
    Receptor-mediated cargo hitchhiking on bulk autophagy.
    Eigo Takeda, Takahiro Isoda, Sachiko Hosokawa, Yu Oikawa, Shukun Hotta-Ren, Alexander I May, Yoshinori Ohsumi.
      While the molecular mechanism of autophagy is well studied, the cargoes delivered by autophagy remain incompletely characterized. To examine the selectivity of autophagy cargo, we conducted proteomics on isolated yeast autophagic bodies, which are intermediate structures in the autophagy process. We identify a protein, Hab1, that is highly preferentially delivered to vacuoles. The N-terminal 42 amino acid region of Hab1 contains an amphipathic helix and an Atg8-family interacting motif, both of which are necessary and sufficient for the preferential delivery of Hab1 by autophagy. We find that fusion of this region with a cytosolic protein results in preferential delivery of this protein to the vacuole. Furthermore, attachment of this region to an organelle allows for autophagic delivery in a manner independent of canonical autophagy receptor or scaffold proteins. We propose a novel mode of selective autophagy in which a receptor, in this case Hab1, binds directly to forming isolation membranes during bulk autophagy.
    Keywords:   Saccharomyces cerevisiae ; Atg8; Autophagy; Hab1; Selective Autophagy
    DOI:  https://doi.org/10.1038/s44318-024-00091-8
  5. Biol Methods Protoc. 2024 ;9(1): bpae026
    Multiparameter flow cytometric detection and analysis of rare cells in in vivo models of cancer metastasis.
    Mikaela M Mallin, Louis T A Rolle, Kenneth J Pienta, Sarah R Amend.
      Rapid and reliable circulating tumor cell (CTC) and disseminated tumor cell (DTC) detection are critical for rigorous evaluation of in vivo metastasis models. Clinical data show that each step of the metastatic cascade presents increasing barriers to success, limiting the number of successful metastatic cells to fewer than 1 in 1,500,000,000. As such, it is critical for scientists to employ approaches that allow for the evaluation of metastatic competency at each step of the cascade. Here, we present a flow cytometry-based method that enables swift and simultaneous comparison of both CTCs and DTCs from single animals, enabling evaluation of multiple metastatic steps within a single model system. We present the necessary gating strategy and optimized sample preparation conditions necessary to capture CTCs and DTCs using this approach. We also provide proof-of-concept experiments emphasizing the appropriate limits of detection of these conditions. Most importantly, we successfully recover CTCs and DTCs from murine blood and bone marrow. In Supplemental materials, we expand the applicability of our method to lung tissue and exemplify a potential multi-plexing strategy to further characterize recovered CTCs and DTCs. This approach to multiparameter flow cytometric detection and analysis of rare cells in in vivo models of metastasis is reproducible, high throughput, broadly applicable, and highly adaptable to a wide range of scientific inquiries. Most notably, it simplifies the recovery and analysis of CTCs and DTCs from the same animal, allowing for a rapid first look at the comparative metastatic competency of various model systems throughout multiple steps of the metastatic cascade.
    Keywords:  circulating tumor cell (CTC); disseminated tumor cell (DTC); flow cytometry (methods); metastasis (cancer metastasis); rare cell detection
    DOI:  https://doi.org/10.1093/biomethods/bpae026
  6. bioRxiv. 2024 May 05. pii: 2024.05.03.592368. [Epub ahead of print]
    In vivo CRISPR screening identifies geranylgeranyl diphosphate as a pancreatic cancer tumor growth dependency.
    Casie S Kubota, Stephanie L Myers, Toni T Seppälä, Richard A Burkhart, Peter J Espenshade.
      Cancer cells must maintain lipid supplies for their proliferation and do so by upregulating lipogenic gene programs. The sterol regulatory element-binding proteins (SREBPs) act as modulators of lipid homeostasis by acting as transcriptional activators of genes required for fatty acid and cholesterol synthesis and uptake. SREBPs have been recognized as chemotherapeutic targets in multiple cancers, however it is not well understood which SREBP target genes are essential for tumorigenesis. Using parallel in vitro and in vivo CRISPR knockout screens, we identified terpenoid backbone biosynthesis genes as essential for pancreatic ductal adenocarcinoma (PDAC) tumor development. Specifically, we identified the non-sterol isoprenoid product of the mevalonate pathway, geranylgeranyl diphosphate (GGPP), as an essential lipid for tumor growth. Mechanistically, we observed that restricting mevalonate pathway activity using statins and SREBP inhibitors synergistically induced apoptosis and caused disruptions in small G protein prenylation that have pleiotropic effects on cellular signaling pathways. Finally, we demonstrated that geranylgeranyl diphosphate synthase 1 ( GGPS1 ) knockdown significantly reduces tumor burden in an orthotopic xenograft mouse model. These findings indicate that PDAC tumors selectively require GGPP over other lipids such as cholesterol and fatty acids and that this is a targetable vulnerability of pancreatic cancer cells.
    DOI:  https://doi.org/10.1101/2024.05.03.592368
  7. Cell Chem Biol. 2024 May 16. pii: S2451-9456(24)00169-7. [Epub ahead of print]31(5): 932-943.e8
    One-carbon unit supplementation fuels purine synthesis in tumor-infiltrating T cells and augments checkpoint blockade.
    Xincheng Xu, Zihong Chen, Caroline R Bartman, Xi Xing, Kellen Olszewski, Joshua D Rabinowitz.
      Nucleotides perform important metabolic functions, carrying energy and feeding nucleic acid synthesis. Here, we use isotope tracing-mass spectrometry to quantitate contributions to purine nucleotides from salvage versus de novo synthesis. We further explore the impact of augmenting a key precursor for purine synthesis, one-carbon (1C) units. We show that tumors and tumor-infiltrating T cells (relative to splenic or lymph node T cells) synthesize purines de novo. Shortage of 1C units for T cell purine synthesis is accordingly a potential bottleneck for anti-tumor immunity. Supplementing 1C units by infusing formate drives formate assimilation into purines in tumor-infiltrating T cells. Orally administered methanol functions as a formate pro-drug, with deuteration enabling kinetic control of formate production. Safe doses of methanol raise formate levels and augment anti-PD-1 checkpoint blockade in MC38 tumors, tripling durable regressions. Thus, 1C deficiency can gate antitumor immunity and this metabolic checkpoint can be overcome with pharmacological 1C supplementation.
    DOI:  https://doi.org/10.1016/j.chembiol.2024.04.007
  8. Sci Signal. 2024 May 14. 17(836): eadq3321
    The lactate wasteland.
    Wei Wong.
      Activation of GPR81 in white adipose tissue by lactate results in cancer-associated cachexia.
    DOI:  https://doi.org/10.1126/scisignal.adq3321
  9. Mol Cancer. 2024 May 18. 23(1): 106
    Aging and cancer.
    Léa Montégut, Carlos López-Otín, Guido Kroemer.
      Aging and cancer exhibit apparent links that we will examine in this review. The null hypothesis that aging and cancer coincide because both are driven by time, irrespective of the precise causes, can be confronted with the idea that aging and cancer share common mechanistic grounds that are referred to as 'hallmarks'. Indeed, several hallmarks of aging also contribute to carcinogenesis and tumor progression, but some of the molecular and cellular characteristics of aging may also reduce the probability of developing lethal cancer, perhaps explaining why very old age (> 90 years) is accompanied by a reduced incidence of neoplastic diseases. We will also discuss the possibility that the aging process itself causes cancer, meaning that the time-dependent degradation of cellular and supracellular functions that accompanies aging produces cancer as a byproduct or 'age-associated disease'. Conversely, cancer and its treatment may erode health and drive the aging process, as this has dramatically been documented for cancer survivors diagnosed during childhood, adolescence, and young adulthood. We conclude that aging and cancer are connected by common superior causes including endogenous and lifestyle factors, as well as by a bidirectional crosstalk, that together render old age not only a risk factor of cancer but also an important parameter that must be considered for therapeutic decisions.
    Keywords:  Age; Chemotherapy; Immunotherapy; Lifestyle; Modifiable risk factors
    DOI:  https://doi.org/10.1186/s12943-024-02020-z
  10. Nanomedicine. 2024 Jan;pii: S1549-9634(23)00065-5. [Epub ahead of print]55 102714
    Exploiting the ferroaddiction of pancreatic cancer cells using Fe-doped nanoparticles.
    Thanpisit Lomphithak, Apiwit Sae-Fung, Simone Sprio, Anna Tampieri, Siriporn Jitkaew, Bengt Fadeel.
      Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with poor survival rates. Here, we evaluated iron-doped hydroxyapatite (FeHA) as a potential nanomedicine-based approach to combat PDAC. FeHA, in combination with a sublethal dose of the glutathione peroxidase 4 (GPX4) inhibitor RSL3, was found to trigger ferroptosis in KRAS mutant PANC-1 cells, but not in BxPC3 cells, while sparing normal human cells (fibroblasts and peripheral blood mononuclear cells). These findings were recapitulated in 3D spheroids generated using PDAC cells harboring wild-type versus mutant KRAS. Moreover, ferroptosis induction by FeHA plus RSL3 was reversed by the knockdown of STEAP3, a metalloreductase responsible for converting Fe3+ to Fe2+. Taken together, our data show that FeHA is capable of triggering cancer cell death in a KRAS-selective, STEAP3-dependent manner in PDAC cells.
    Keywords:  Ferroptosis; KRAS; Nanomedicine; Pancreatic adenocarcinoma; STEAP3
    DOI:  https://doi.org/10.1016/j.nano.2023.102714
  11. Cell Rep Med. 2024 Apr 30. pii: S2666-3791(24)00249-0. [Epub ahead of print] 101557
    GATA6 identifies an immune-enriched phenotype linked to favorable outcomes in patients with pancreatic cancer undergoing upfront surgery.
    Dutch Pancreatic Cancer Group (DPCG)
      This study underscores GATA6's role in distinguishing classical and basal-like pancreatic ductal adenocarcinoma (PDAC) phenotypes. Retrospective studies associate GATA6 immunohistochemistry (IHC) expression with survival outcomes, warranting prospective validation. In a prospective treatment-naive cohort of patients with resected PDAC, GATA6 IHC proves a prognostic discriminator, associating high GATA6 expression with extended survival and the classical PDAC phenotype. However, GATA6's prognostic significance is numerically lower after gemcitabine-based neoadjuvant chemoradiotherapy compared to its significance in patients treated with upfront surgery. Furthermore, GATA6 is implicated in immunomodulation, although a comprehensive investigation of its immunological role is lacking. Treatment-naive PDAC tumors with varying GATA6 expression yield distinct immunological landscapes. Tumors highly expressing GATA6 show reduced infiltration of immunosuppressive regulatory T cells and M2 macrophages but increased infiltration of immune-stimulating, antigen-presenting, and activated T cells. Our findings caution against solely relying on GATA6 for molecular subtyping in clinical trials and open avenues for exploring immune-based combination therapies.
    Keywords:  GATA6; PDAC; immune profiling; pancreatic ductal adenocarcinoma; randomized controlled trial; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.xcrm.2024.101557
  12. Autophagy. 2024 May 14. 1-2
    A delicate decision between repair and degradation of damaged lysosomes.
    Yuchen Lei, Daniel J Klionsky.
      The destination of a damaged lysosome is either being repaired if the damage is small or degraded through a lysosome-specific macroautophagy/autophagy pathway named lysophagy when the damage is too extensive to repair. Even though previous studies report lumenal glycan exposure during lysosome damage as a signal to trigger lysophagy, it is possibly beneficial for cells to initiate lysophagy earlier than membrane rupture. In a recently published article, Gahlot et al. determined that SPART/SPG20 senses lipid-packing defects and recruits and activates the ubiquitin ligase ITCH, which labels damaged lysosomes with ubiquitin chains to initiate lysophagy.
    Keywords:  ESCRT; lipid-packing defect; lysophagy; lysosome damage; ubiquitination
    DOI:  https://doi.org/10.1080/15548627.2024.2350738
  13. Cell Rep. 2024 May 10. pii: S2211-1247(24)00552-7. [Epub ahead of print]43(5): 114224
    Palmitoyl transferase ZDHHC20 promotes pancreatic cancer metastasis.
    Goran Tomić, Clare Sheridan, Alice Y Refermat, Marc P Baggelaar, James Sipthorp, Bhuvana Sudarshan, Cory A Ocasio, Alejandro Suárez-Bonnet, Simon L Priestnall, Eleanor Herbert, Edward W Tate, Julian Downward.
      Metastasis is one of the defining features of pancreatic ductal adenocarcinoma (PDAC) that contributes to poor prognosis. In this study, the palmitoyl transferase ZDHHC20 was identified in an in vivo short hairpin RNA (shRNA) screen as critical for metastatic outgrowth, with no effect on proliferation and migration in vitro or primary PDAC growth in mice. This phenotype is abrogated in immunocompromised animals and animals with depleted natural killer (NK) cells, indicating that ZDHHC20 affects the interaction of tumor cells and the innate immune system. Using a chemical genetics platform for ZDHHC20-specific substrate profiling, a number of substrates of this enzyme were identified. These results describe a role for palmitoylation in enabling distant metastasis that could not have been detected using in vitro screening approaches and identify potential effectors through which ZDHHC20 promotes metastasis of PDAC.
    Keywords:  CP: Cancer
    DOI:  https://doi.org/10.1016/j.celrep.2024.114224
  14. Nature. 2024 May;629(8012): 543-554
    Decoding the interplay between genetic and non-genetic drivers of metastasis.
    Panagiotis Karras, James R M Black, Nicholas McGranahan, Jean-Christophe Marine.
      Metastasis is a multistep process by which cancer cells break away from their original location and spread to distant organs, and is responsible for the vast majority of cancer-related deaths. Preventing early metastatic dissemination would revolutionize the ability to fight cancer. Unfortunately, the relatively poor understanding of the molecular underpinnings of metastasis has hampered the development of effective anti-metastatic drugs. Although it is now accepted that disseminating tumour cells need to acquire multiple competencies to face the many obstacles they encounter before reaching their metastatic site(s), whether these competencies are acquired through an accumulation of metastasis-specific genetic alterations and/or non-genetic events is often debated. Here we review a growing body of literature highlighting the importance of both genetic and non-genetic reprogramming events during the metastatic cascade, and discuss how genetic and non-genetic processes act in concert to confer metastatic competencies. We also describe how recent technological advances, and in particular the advent of single-cell multi-omics and barcoding approaches, will help to better elucidate the cross-talk between genetic and non-genetic mechanisms of metastasis and ultimately inform innovative paths for the early detection and interception of this lethal process.
    DOI:  https://doi.org/10.1038/s41586-024-07302-6
  15. Immunity. 2024 May 10. pii: S1074-7613(24)00226-7. [Epub ahead of print]
    Expression of the membrane tetraspanin claudin 18 on cancer cells promotes T lymphocyte infiltration and antitumor immunity in pancreatic cancer.
    Francesco De Sanctis, Silvia Dusi, Simone Caligola, Cristina Anselmi, Varvara Petrova, Barbara Rossi, Gabriele Angelini, Michael Erdeljan, Stefan Wöll, Anna Melissa Schlitter, Thomas Metzler, Katja Steiger, Zea Borok, Peter Bailey, Aline Bauer, Cornelia Halin, Federico Boschi, Rosalba Giugno, Stefania Canè, Rita Lawlor, Vincenzo Corbo, Aldo Scarpa, Gabriela Constantin, Stefano Ugel, Fulvia Vascotto, Ugur Sahin, Özlem Türeci, Vincenzo Bronte.
      Tumors weakly infiltrated by T lymphocytes poorly respond to immunotherapy. We aimed to unveil malignancy-associated programs regulating T cell entrance, arrest, and activation in the tumor environment. Differential expression of cell adhesion and tissue architecture programs, particularly the presence of the membrane tetraspanin claudin (CLDN)18 as a signature gene, demarcated immune-infiltrated from immune-depleted mouse pancreatic tumors. In human pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer, CLDN18 expression positively correlated with more differentiated histology and favorable prognosis. CLDN18 on the cell surface promoted accrual of cytotoxic T lymphocytes (CTLs), facilitating direct CTL contacts with tumor cells by driving the mobilization of the adhesion protein ALCAM to the lipid rafts of the tumor cell membrane through actin. This process favored the formation of robust immunological synapses (ISs) between CTLs and CLDN18-positive cancer cells, resulting in increased T cell activation. Our data reveal an immune role for CLDN18 in orchestrating T cell infiltration and shaping the tumor immune contexture.
    Keywords:  ALCAM; CD8(+) T lymphocytes; T lymphocyte infiltration; adhesion molecule; adoptive cell therapy; claudin 18; immunological synapse; pancreatic cancer; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.immuni.2024.04.021
  16. J Pathol Clin Res. 2024 May;10(3): e12377
    KRT81 and HNF1A expression in pancreatic ductal adenocarcinoma: investigation of predictive and prognostic value of immunohistochemistry-based subtyping.
    Jia Rao, Marianne Sinn, Uwe Pelzer, Hanno Riess, Helmut Oettle, Ihsan E Demir, Helmut Friess, Carsten Jäger, Katja Steiger, Alexander Muckenhuber.
      Even after decades of research, pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal disease and responses to conventional treatments remain mostly poor. Subclassification of PDAC into distinct biological subtypes has been proposed by various groups to further improve patient outcome and reduce unnecessary side effects. Recently, an immunohistochemistry (IHC)-based subtyping method using cytokeratin-81 (KRT81) and hepatocyte nuclear factor 1A (HNF1A) could recapitulate some of the previously established molecular subtyping methods, while providing significant prognostic and, to a limited degree, also predictive information. We refined the KRT81/HNF1A subtyping method to classify PDAC into three distinct biological subtypes. The prognostic value of the IHC-based method was investigated in two primary resected cohorts, which include 269 and 286 patients, respectively. In the second cohort, we also assessed the predictive effect for response to erlotinib + gemcitabine. In both PDAC cohorts, the new HNF1A-positive subtype was associated with the best survival, the KRT81-positive subtype with the worst, and the double-negative with an intermediate survival (p < 0.001 and p < 0.001, respectively) in univariate and multivariate analyses. In the second cohort (CONKO-005), the IHC-based subtype was additionally found to have a potential predictive value for the erlotinib-based treatment effect. The revised IHC-based subtyping using KRT81 and HNF1A has prognostic significance for PDAC patients and may be of value in predicting treatment response to specific therapeutic agents.
    Keywords:  HNF1A; KRT81; biomarker; erlotinib; immunohistochemistry; pancreatic cancer; predictive; prognostic
    DOI:  https://doi.org/10.1002/2056-4538.12377
  17. Mol Cell. 2024 May 16. pii: S1097-2765(24)00383-6. [Epub ahead of print]84(10): 1980-1994.e8
    Autophagy preferentially degrades non-fibrillar polyQ aggregates.
    Dorothy Y Zhao, Felix J B Bäuerlein, Itika Saha, F Ulrich Hartl, Wolfgang Baumeister, Florian Wilfling.
      Aggregation of proteins containing expanded polyglutamine (polyQ) repeats is the cytopathologic hallmark of a group of dominantly inherited neurodegenerative diseases, including Huntington's disease (HD). Huntingtin (Htt), the disease protein of HD, forms amyloid-like fibrils by liquid-to-solid phase transition. Macroautophagy has been proposed to clear polyQ aggregates, but the efficiency of aggrephagy is limited. Here, we used cryo-electron tomography to visualize the interactions of autophagosomes with polyQ aggregates in cultured cells in situ. We found that an amorphous aggregate phase exists next to the radially organized polyQ fibrils. Autophagosomes preferentially engulfed this amorphous material, mediated by interactions between the autophagy receptor p62/SQSTM1 and the non-fibrillar aggregate surface. In contrast, amyloid fibrils excluded p62 and evaded clearance, resulting in trapping of autophagic structures. These results suggest that the limited efficiency of autophagy in clearing polyQ aggregates is due to the inability of autophagosomes to interact productively with the non-deformable, fibrillar disease aggregates.
    Keywords:  aggrephagy; amyloid fibril; autophagy; cryo-electron microscopy; cryo-electron tomography; neurodegeneration; p62/SQSTM1/sequestosome 1; phase separation; polyglutamine/polyQ expansion; protein aggregation
    DOI:  https://doi.org/10.1016/j.molcel.2024.04.018
  18. Mol Cancer. 2024 May 16. 23(1): 103
    NEMO/NF-κB signaling functions as a double-edged sword in PanIN formation versus progression to pancreatic cancer.
    Miltiadis Tsesmelis, Ulrike F G Büttner, Melanie Gerstenlauer, Uta Manfras, Konstantinos Tsesmelis, Ziwei Du, Nadine Sperb, Stephanie Ellen Weissinger, Peter Möller, Thomas F E Barth, Harald J Maier, Lap Kwan Chan, Thomas Wirth.
      BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is marked by a dismal survival rate, lacking effective therapeutics due to its aggressive growth, late-stage diagnosis, and chemotherapy resistance. Despite debates on NF-κB targeting for PDAC treatment, no successful approach has emerged.METHODS: To elucidate the role of NF-κB, we ablated NF-κB essential modulator (NEMO), critical for conventional NF-κB signaling, in the pancreata of mice that develop precancerous lesions (KC mouse model). Secretagogue-induced pancreatitis by cerulein injections was utilized to promote inflammation and accelerate PDAC development.
    RESULTS: NEMO deletion reduced fibrosis and inflammation in young KC mice, resulting in fewer pancreatic intraepithelial neoplasias (PanINs) at later stages. Paradoxically, however, NEMO deletion accelerated the progression of these fewer PanINs to PDAC and reduced median lifespan. Further, analysis of tissue microarrays from human PDAC sections highlighted the correlation between reduced NEMO expression in neoplastic cells and poorer prognosis, supporting our observation in mice. Mechanistically, NEMO deletion impeded oncogene-induced senescence (OIS), which is normally active in low-grade PanINs. This blockage resulted in fewer senescence-associated secretory phenotype (SASP) factors, reducing inflammation. However, blocked OIS fostered replication stress and DNA damage accumulation which accelerated PanIN progression to PDAC. Finally, treatment with the DNA damage-inducing reagent etoposide resulted in elevated cell death in NEMO-ablated PDAC cells compared to their NEMO-competent counterparts, indicative of a synthetic lethality paradigm.
    CONCLUSIONS: NEMO exhibited both oncogenic and tumor-suppressive properties during PDAC development. Caution is suggested in therapeutic interventions targeting NF-κB, which may be detrimental during PanIN progression but beneficial post-PDAC development.
    Keywords:  Cerulein; NEMO; NF-κB; PDAC; PanINs; Pancreatitis; Senescence
    DOI:  https://doi.org/10.1186/s12943-024-01989-x
  19. Cell Rep Methods. 2024 May 08. pii: S2667-2375(24)00118-8. [Epub ahead of print] 100774
    Methods for making and observing model lipid droplets.
    Sonali A Gandhi, Shahnaz Parveen, Munirah Alduhailan, Ramesh Tripathi, Nasser Junedi, Mohammad Saqallah, Matthew A Sanders, Peter M Hoffmann, Katherine Truex, James G Granneman, Christopher V Kelly.
      We present methods for making and testing the membrane biophysics of model lipid droplets (LDs). Methods are described for imaging LDs ranging in size from 0.1 to 40 μm in diameter with high-resolution microscopy and spectroscopy. With known LD compositions, membrane binding, sorting, diffusion, and tension were measured via fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP), fluorescence lifetime imaging microscopy (FLIM), atomic force microscopy (AFM), and imaging flow cytometry. Additionally, a custom, small-volume pendant droplet tensiometer is described and used to measure the association of phospholipids to the LD surface. These complementary, cross-validating methods of measuring LD membrane behavior reveal the interplay of biophysical processes on lipid droplet monolayers.
    Keywords:  AFM; CP: Biotechnology; CP: Cell biology; FCS; FLIM; FRAP; atomic force microscopy; diffusion; fluorescence correlation spectroscopy; fluorescence lifetime imaging microscopy; fluorescence microscopy; fluorescence recovery after photobleaching; model lipid droplets; pendant droplet tensiometry; phospholipid monolayers; sorting; tension
    DOI:  https://doi.org/10.1016/j.crmeth.2024.100774
  20. Soft Matter. 2024 May 17.
    Methyl-β-cyclodextrin asymmetrically extracts phospholipid from bilayers, granting tunable control over differential stress in lipid vesicles.
    Tyler Reagle, Yuxin Xie, Zheyuan Li, Warner Carnero, Tobias Baumgart.
      Lipid asymmetry - that is, a nonuniform lipid distribution between the leaflets of a bilayer - is a ubiquitous feature of biomembranes and is implicated in several cellular phenomena. Differential tension - that is, unequal lateral monolayer tensions comparing the leaflets of a bilayer- is closely associated with lipid asymmetry underlying these varied roles. Because differential tension is not directly measurable in combination with the fact that common methods to adjust this quantity grant only semi-quantitative control over it, a detailed understanding of lipid asymmetry and differential tension are impeded. To overcome these challenges, we leveraged reversible complexation of phospholipid by methyl-β-cyclodextrin (mbCD) to tune the direction and magnitude of lipid asymmetry in synthetic vesicles. Lipid asymmetry generated in our study induced (i) vesicle shape changes and (ii) gel-liquid phase coexistence in 1-component vesicles. By applying mass-action considerations to interpret our findings, we discuss how this approach provides access to phospholipid thermodynamic potentials in bilayers containing lipid asymmetry (which are coupled to the differential tension of a bilayer). Because lipid asymmetry yielded by our approach is (i) tunable and (ii) maintained over minute to hour timescales, we anticipate that this approach will be a valuable addition to the experimental toolbox for systematic investigation into the biophysical role(s) of lipid asymmetry (and differential tension).
    DOI:  https://doi.org/10.1039/d3sm01772a
  21. Proc Natl Acad Sci U S A. 2024 May 21. 121(21): e2403685121
    Genome-wide CRISPR screens in spheroid culture reveal that the tumor suppressor LKB1 inhibits growth via the PIKFYVE lipid kinase.
    John R Ferrarone, Jerin Thomas, Arun M Unni, Yuxiang Zheng, Michal J Nagiec, Eric E Gardner, Oksana Mashadova, Kate Li, Nikos Koundouros, Antonino Montalbano, Meer Mustafa, Lewis C Cantley, John Blenis, Neville E Sanjana, Harold Varmus.
      The tumor suppressor LKB1 is a serine/threonine protein kinase that is frequently mutated in human lung adenocarcinoma (LUAD). LKB1 regulates a complex signaling network that is known to control cell polarity and metabolism; however, the pathways that mediate the tumor-suppressive activity of LKB1 are incompletely defined. To identify mechanisms of LKB1-mediated growth suppression, we developed a spheroid-based cell culture assay to study LKB1-dependent growth. We then performed genome-wide CRISPR screens in spheroidal culture and found that LKB1 suppresses growth, in part, by activating the PIKFYVE lipid kinase. Finally, we used chemical inhibitors and a pH-sensitive reporter to determine that LKB1 impairs growth by promoting the internalization of wild-type EGFR in a PIKFYVE-dependent manner.
    Keywords:  EGFR; LKB1; PIKFYVE; STK11
    DOI:  https://doi.org/10.1073/pnas.2403685121
  22. Nat Commun. 2024 May 17. 15(1): 3812
    High-throughput mechanical phenotyping and transcriptomics of single cells.
    Akifumi Shiomi, Taikopaul Kaneko, Kaori Nishikawa, Arata Tsuchida, Takashi Isoshima, Mayuko Sato, Kiminori Toyooka, Kentaro Doi, Hidekazu Nishikii, Hirofumi Shintaku.
      The molecular system regulating cellular mechanical properties remains unexplored at single-cell resolution mainly due to a limited ability to combine mechanophenotyping with unbiased transcriptional screening. Here, we describe an electroporation-based lipid-bilayer assay for cell surface tension and transcriptomics (ELASTomics), a method in which oligonucleotide-labelled macromolecules are imported into cells via nanopore electroporation to assess the mechanical state of the cell surface and are enumerated by sequencing. ELASTomics can be readily integrated with existing single-cell sequencing approaches and enables the joint study of cell surface mechanics and underlying transcriptional regulation at an unprecedented resolution. We validate ELASTomics via analysis of cancer cell lines from various malignancies and show that the method can accurately identify cell types and assess cell surface tension. ELASTomics enables exploration of the relationships between cell surface tension, surface proteins, and transcripts along cell lineages differentiating from the haematopoietic progenitor cells of mice. We study the surface mechanics of cellular senescence and demonstrate that RRAD regulates cell surface tension in senescent TIG-1 cells. ELASTomics provides a unique opportunity to profile the mechanical and molecular phenotypes of single cells and can dissect the interplay among these in a range of biological contexts.
    DOI:  https://doi.org/10.1038/s41467-024-48088-5
  23. bioRxiv. 2024 May 05. pii: 2024.05.02.592216. [Epub ahead of print]
    "Tumor-selective treatment of metastatic pancreatic cancer with an engineered, probiotic living drug".
    Amanda R Decker-Farrell, Stephen A Sastra, Tetsuhiro Harimoto, Marie C Hasselluhn, Carmine F Palermo, Edward R Ballister, Michael A Badgley, Tal Danino, Kenneth P Olive.
      Pancreatic ductal adenocarcinoma (PDAC) poses significant challenges for effective treatment, with systemic chemotherapy often proving inadequate due to poor drug delivery and the tumor's immunosuppressive microenvironment. Engineered bacteria present a novel approach to target PDAC, leveraging their ability to colonize tumors and deliver therapeutic payloads. Here, we engineered probiotic Escherichia coli Nissle 1917 (EcN) to produce the pore-forming Theta toxin (Nis-Theta) and evaluated its efficacy in a preclinical model of PDAC. Probiotic administration resulted in selective colonization of tumor tissue, leading to improved overall survival compared to standard chemotherapy. Moreover, this strain exhibited cytotoxic effects on both primary and distant tumor lesions while sparing normal tissues. Importantly, treatment also modulated the tumor microenvironment by increasing anti-tumor immune cell populations and reducing immunosuppressive markers. These findings demonstrate the potential of engineered probiotic bacteria as a safe and effective therapeutic approach for PDAC, offering promise for improved patient outcomes.
    DOI:  https://doi.org/10.1101/2024.05.02.592216
  24. Bio Protoc. 2024 May 05. 14(9): e4986
    Quantitative Measurement of Plasma Membrane Protein Internalisation and Recycling in Heterogenous Cellular Samples by Flow Cytometry.
    Hui Jing Lim, Hamish E G McWilliam.
      Plasma membrane proteins mediate important aspects of physiology, including nutrient acquisition, cell-cell interactions, and monitoring homeostasis. The trafficking of these proteins, involving internalisation from and/or recycling back to the cell surface, is often critical to their functions. These processes can vary among different proteins and cell types and states and are still being elucidated. Current strategies to measure surface protein internalisation and recycling are typically microscopy or biochemical assays; these are accurate but generally limited to analysing a homogenous cell population and are often low throughput. Here, we present flow cytometry-based methods involving probe-conjugated antibodies that enable quantification of internalisation or recycling rates at the single-cell level in complex samples. To measure internalisation, we detail an assay where the protein of interest is labelled with a specific antibody conjugated to a fluorescent oligonucleotide-labelled probe. To measure recycling, a specific antibody conjugated to a cleavable biotin group is employed. These probes permit the differentiation of molecules that have been internalised or recycled from those that have not. When combined with cell-specific marker panels, these methods allow the quantitative study of plasma membrane protein trafficking dynamics in a heterogenous cell mixture at the single-cell level. Key features • These assays allow sensitive quantification of internalised or recycled surface molecules using oligonucleotide or cleavable biotin-conjugated probes, respectively, and detected by flow cytometry. • They can be adapted to any membrane protein that transits via the cell surface and for which a specific purified antibody is available. • The dynamics of a cell surface protein can be measured in heterogenous cell populations simultaneously, including various cellular activation states. • The internalisation assay builds upon the method developed by Liu et al. [1,2] and extends its application to heterogenous human peripheral blood mononuclear cells. • These assays have been extensively used on suspension cells but have not been tested on adherent cells.
    Keywords:  Cleavable biotin-antibody probe; Flow cytometry; Major histocompatibility complex (MHC) molecules; Oligonucleotide-antibody probe; Plasma membrane; Protein internalisation; Protein recycling; Protein trafficking
    DOI:  https://doi.org/10.21769/BioProtoc.4986
  25. Cancer Metastasis Rev. 2024 May 11.
    The roles of PD-L1 in the various stages of tumor metastasis.
    Yinjun He, Ming Zhu, Xuan Lai, Honghe Zhang, Weiqin Jiang.
      The interaction between tumor programmed death ligand 1 (PD-L1) and T-cell programmed cell death 1 (PD-1) has long been acknowledged as a mechanism for evading immune surveillance. Recent studies, however, have unveiled a more nuanced role of tumor-intrinsic PD-L1 in reprograming tumoral phenotypes. Preclinical models emphasize the synchronized effects of both intracellular and extracellular PD-L1 in promoting metastasis, with intricate interactions with the immune system. This review aims to summarize recent findings to elucidate the spatiotemporal heterogeneity of PD-L1 expression and the pro-metastatic roles of PD-L1 in the entire process of tumor metastasis. For example, PD-L1 regulates the epithelial-to-mesenchymal transition (EMT) process, facilitates the survival of circulating tumor cells, and induces the formation of immunosuppressive environments at pre-metastatic niches and metastatic sites. And the complexed and dynamic regulation process of PD-L1 for tumor metastasis is related to the spatiotemporal heterogeneity of PD-L1 expression and functions from tumor primary sites to various metastatic sites. This review extends the current understandings for the roles of PD-L1 in mediating tumor metastasis and provides new insights into therapeutic decisions in clinical practice.
    Keywords:  EMT; PD-L1; heterogeneity; immune evasion; metastasis
    DOI:  https://doi.org/10.1007/s10555-024-10189-4
  26. Phys Rev Lett. 2024 May 03. 132(18): 188402
    Membrane Tilt Drives Phase Separation of Adhesion Receptors.
    Shao-Zhen Lin, Rishita Changede, Aaron J Farrugia, Alexander D Bershadsky, Michael P Sheetz, Jacques Prost, Jean-François Rupprecht.
      Cell adhesion receptors are transmembrane proteins that bind cells to their environment. These proteins typically cluster into disk-shaped or linear structures. Here, we show that such clustering patterns spontaneously emerge when the receptor senses the membrane deformation gradient, for example, by reaching a lower-energy conformation when the membrane is tilted relative to the underlying binding substrate. Increasing the strength of the membrane gradient-sensing mechanism first yields isolated disk-shaped clusters and then long linear structures. Our theory is coherent with experimental estimates of the parameters, suggesting that a tilt-induced clustering mechanism is relevant in the context of cell adhesion.
    DOI:  https://doi.org/10.1103/PhysRevLett.132.188402
  27. Curr Opin Struct Biol. 2024 May 12. pii: S0959-440X(24)00058-7. [Epub ahead of print]87 102831
    Making the cut: Multiscale simulation of membrane remodeling.
    Jeriann Beiter, Gregory A Voth.
      Biological membranes are dynamic heterogeneous materials, and their shape and organization are tightly coupled to the properties of the proteins in and around them. However, the length scales of lipid and protein dynamics are far below the size of membrane-bound organelles, much less an entire cell. Therefore, multiscale modeling approaches are often necessary to build a comprehensive picture of the interplay of these factors, and have provided critical insights into our understanding of membrane dynamics. Here, we review computational methods for studying membrane remodeling, as well as passive and active examples of protein-driven membrane remodeling. As the field advances towards the modeling of key aspects of organelles and whole cells - an increasingly accessible regime of study - we summarize here recent successes and offer comments on future trends.
    DOI:  https://doi.org/10.1016/j.sbi.2024.102831
  28. Gut. 2024 May 16. pii: gutjnl-2023-330995. [Epub ahead of print]
    The Peptidoglycan Recognition Protein 1 confers immune evasive properties on pancreatic cancer stem cells.
    Juan Carlos López-Gil, Susana García-Silva, Laura Ruiz-Cañas, Diego Navarro, Adrián Palencia-Campos, Antonio Giráldez-Trujillo, Julie Earl, Jorge Dorado, Gonzalo Gómez-López, Ana Monfort-Vengut, Sonia Alcalá, Matthias M Gaida, Sandra García-Mulero, Pablo Cabezas-Sáinz, Sandra Batres-Ramos, Emma Barreto, Patricia Sánchez-Tomero, Mireia Vallespinós, Leah Ambler, Meng-Lay Lin, Alexandra Aicher, Ana García García de Paredes, Carolina de la Pinta, Alfonso Sanjuanbenito, Ignacio Ruz-Caracuel, Mercedes Rodríguez-Garrote, Carmen Guerra, Alfredo Carrato, Guillermo de Cárcer, Laura Sánchez, César Nombela-Arrieta, Elisa Espinet, Víctor Javier Sanchez-Arevalo Lobo, Christopher Heeschen, Bruno Sainz.
      OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) has limited therapeutic options, particularly with immune checkpoint inhibitors. Highly chemoresistant 'stem-like' cells, known as cancer stem cells (CSCs), are implicated in PDAC aggressiveness. Thus, comprehending how this subset of cells evades the immune system is crucial for advancing novel therapies.DESIGN: We used the KPC mouse model (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) and primary tumour cell lines to investigate putative CSC populations. Transcriptomic analyses were conducted to pinpoint new genes involved in immune evasion. Overexpressing and knockout cell lines were established with lentiviral vectors. Subsequent in vitro coculture assays, in vivo mouse and zebrafish tumorigenesis studies, and in silico database approaches were performed.
    RESULTS: Using the KPC mouse model, we functionally confirmed a population of cells marked by EpCAM, Sca-1 and CD133 as authentic CSCs and investigated their transcriptional profile. Immune evasion signatures/genes, notably the gene peptidoglycan recognition protein 1 (PGLYRP1), were significantly overexpressed in these CSCs. Modulating PGLYRP1 impacted CSC immune evasion, affecting their resistance to macrophage-mediated and T-cell-mediated killing and their tumourigenesis in immunocompetent mice. Mechanistically, tumour necrosis factor alpha (TNFα)-regulated PGLYRP1 expression interferes with the immune tumour microenvironment (TME) landscape, promoting myeloid cell-derived immunosuppression and activated T-cell death. Importantly, these findings were not only replicated in human models, but clinically, secreted PGLYRP1 levels were significantly elevated in patients with PDAC.
    CONCLUSIONS: This study establishes PGLYRP1 as a novel CSC-associated marker crucial for immune evasion, particularly against macrophage phagocytosis and T-cell killing, presenting it as a promising target for PDAC immunotherapy.
    Keywords:  CANCER IMMUNOBIOLOGY; IMMUNE RESPONSE; PANCREATIC CANCER; STEM CELLS
    DOI:  https://doi.org/10.1136/gutjnl-2023-330995
  29. Mol Cell. 2024 May 16. pii: S1097-2765(24)00324-1. [Epub ahead of print]84(10): 1964-1979.e6
    Unraveling ETC complex I function in ferroptosis reveals a potential ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers.
    Chao Mao, Guang Lei, Amber Horbath, Min Wang, Zhengze Lu, Yuelong Yan, Xiaoguang Liu, Lavanya Kondiparthi, Xiong Chen, Jun Cheng, Qidong Li, Zhihao Xu, Li Zhuang, Bingliang Fang, Joseph R Marszalek, Masha V Poyurovsky, Kellen Olszewski, Boyi Gan.
      The role of the mitochondrial electron transport chain (ETC) in regulating ferroptosis is not fully elucidated. Here, we reveal that pharmacological inhibition of the ETC complex I reduces ubiquinol levels while decreasing ATP levels and activating AMP-activated protein kinase (AMPK), the two effects known for their roles in promoting and suppressing ferroptosis, respectively. Consequently, the impact of complex I inhibitors on ferroptosis induced by glutathione peroxidase 4 (GPX4) inhibition is limited. The pharmacological inhibition of complex I in LKB1-AMPK-inactivated cells, or genetic ablation of complex I (which does not trigger apparent AMPK activation), abrogates the AMPK-mediated ferroptosis-suppressive effect and sensitizes cancer cells to GPX4-inactivation-induced ferroptosis. Furthermore, complex I inhibition synergizes with radiotherapy (RT) to selectively suppress the growth of LKB1-deficient tumors by inducing ferroptosis in mouse models. Our data demonstrate a multifaceted role of complex I in regulating ferroptosis and propose a ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers.
    Keywords:  AMPK; ETC complex I; LKB1; cancer therapy; ferroptosis; lipid peroxidation; mitochondria
    DOI:  https://doi.org/10.1016/j.molcel.2024.04.009
  30. Langmuir. 2024 May 16.
    Measuring the Transmembrane Registration of Lipid Domains in Droplet Interface Bilayers through Tensiometry.
    Braydon G Segars, Michelle Makhoul-Mansour, Joyce Beyrouthy, Eric C Freeman.
      Diverse collections of lipids self-assemble into domains within biological membranes, and these domains are typically organized in both the transverse and lateral directions of the membrane. The ability of the membrane to link these domains across the membrane's interior grants cells control over features on the external cellular surface. Numerous hypothesized factors drive the cross-membrane (or transverse) coupling of lipid domains. In this work we seek to isolate these transverse lipid-lipid influences in a simple model system using droplet interface bilayers (DIBs) to better understand the associated mechanics. DIBs enable symmetric and asymmetric combinations of domain-forming lipid mixtures within a model bilayer, and the evolving energetics of the membrane may be tracked using drop-shape analysis. We find that symmetric distributions of domain-forming lipids produce long-lasting, gradual shifts in the DIB membrane energetics that are not observed in asymmetric distributions of the lipids where the domain-forming lipids are only within one leaflet. The approach selected for this work provides experimental measurement of the mismatch penalty associated with antiregistered lipid domains as well as measurements of the influence of rafts on DIB behaviors with suggestions for their future use as a model platform.
    DOI:  https://doi.org/10.1021/acs.langmuir.4c00958
  31. J Gene Med. 2024 May;26(5): e3691
    Genetically predicted blood metabolites mediate the association between circulating immune cells and pancreatic cancer: A Mendelian randomization study.
    Guo Zhao, Yuanting Cai, Yuning Wang, Yuan Fang, Shuhang Wang, Ning Li.
      BACKGROUND: Pancreatic cancer is characterized by metabolic dysregulation and unique immunological profiles. Nevertheless, the comprehensive understanding of immune and metabolic dysregulation of pancreatic cancer remains unclear. In the present study, we aimed to investigate the causal relationship of circulating immune cells and pancreatic cancer and identify the blood metabolites as potential mediators.METHODS: The exposure and outcome genome-wide association studies (GWAS) data used in the present study were obtained from the GWAS open-access database (https://gwas.mrcieu.ac.uk). The study used 731 circulating immune cell features, 1400 types of blood metabolites and pancreatic cancer from GWAS. We then performed bidirectional Mendelian randomization (MR) analyses to explore the causal relationships between the circulating immune cells and pancreatic cancer, and two-step MR to discover potential mediating blood metabolites in this process. All statistical analyses were performed in R software. The STROBE-MR (i.e. Strengthening the Reporting of Observational Studies in Epidemiology using Mendelian Randomization) checklist for the reporting of MR studies was also used.
    RESULTS: MR analysis identified seven types of circulating immune cells causally associated with pancreatic cancer. Furthermore, there was no strong evidence that genetically predicted pancreatic cancer had an effect on these seven types of circulating immune cells. Further two-step MR analysis found 10 types of blood metabolites were causally associated with pancreatic cancer and the associations between circulating CD39+CD8+ T cells and pancreatic cancer were mediated by blood orotates with proportions of 5.18% (p = 0.016).
    CONCLUSIONS: The present study provides evidence supporting the causal relationships between various circulating immune cells, especially CD39+CD8+ T cells, and pancreatic cancer, with a potential effect mediated by blood orotates. Further research is needed on additional risk factors as potential mediators and establish a comprehensive immunity-metabolism network in pancreatic cancer.
    Keywords:  CD39+CD8+ T cells; Mendelian randomization; blood metabolites; circulating immune cells; orotate levels; pancreatic cancer
    DOI:  https://doi.org/10.1002/jgm.3691
  32. Commun Biol. 2024 May 15. 7(1): 574
    Impairing hydrolase transport machinery prevents human melanoma metastasis.
    Alice Nordlinger, Justine Del Rio, Shivang Parikh, Laetitia Thomas, Roma Parikh, Hananya Vaknine, Ronen Brenner, Francesco Baschieri, Aude Robert, Mehdi Khaled.
      Metastases are the major cause of cancer-related death, yet, molecular weaknesses that could be exploited to prevent tumor cells spreading are poorly known. Here, we found that perturbing hydrolase transport to lysosomes by blocking either the expression of IGF2R, the main receptor responsible for their trafficking, or GNPT, a transferase involved in the addition of the specific tag recognized by IGF2R, reduces melanoma invasiveness potential. Mechanistically, we demonstrate that the perturbation of this traffic, leads to a compensatory lysosome neo-biogenesis devoided of degradative enzymes. This regulatory loop relies on the stimulation of TFEB transcription factor expression. Interestingly, the inhibition of this transcription factor playing a key role of lysosome production, restores melanomas' invasive potential in the absence of hydrolase transport. These data implicate that targeting hydrolase transport in melanoma could serve to develop new therapies aiming to prevent metastasis by triggering a physiological response stimulating TFEB expression in melanoma.
    DOI:  https://doi.org/10.1038/s42003-024-06261-y
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