bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2024‒01‒21
thirty-one papers selected by
Kıvanç Görgülü, Technical University of Munich



  1. bioRxiv. 2023 Dec 30. pii: 2023.12.30.573100. [Epub ahead of print]
      Control of cell identity and number is central to tissue function, yet principles governing organization of malignant cells in tumor tissues remain poorly understood. Using mathematical modeling and candidate-based analysis, we discover primary and metastatic pancreatic ductal adenocarcinoma (PDAC) organize in a stereotypic pattern whereby PDAC cells responding to WNT signals (WNT-R) neighbor WNT-secreting cancer cells (WNT-S). Leveraging lineage-tracing, we reveal the WNT-R state is transient and gives rise to the WNT-S state that is highly stable and committed to organizing malignant tissue. We further show that a subset of WNT-S cells expressing the Notch ligand DLL1 form a functional niche for WNT-R cells. Genetic inactivation of WNT secretion or Notch pathway components, or cytoablation of the WNT-S state disrupts PDAC tissue organization, suppressing tumor growth and metastasis. This work indicates PDAC growth depends on an intricately controlled equilibrium of functionally distinct cancer cell states, uncovering a fundamental principle governing solid tumor growth and revealing new opportunities for therapeutic intervention.
    DOI:  https://doi.org/10.1101/2023.12.30.573100
  2. J Pathol. 2024 Jan 17.
      MAP4K4 is a serine/threonine kinase of the STE20 family involved in the regulation of actin cytoskeleton dynamics and cell motility. It has been proposed as a target of angiogenesis and inhibitors show potential in cardioprotection. MAP4K4 also mediates cell invasion in vitro, is overexpressed in various types of cancer, and is associated with poor patient prognosis. Recently, MAP4K4 has been shown to be overexpressed in pancreatic cancer, but its role in tumour initiation, progression, and metastasis is unknown. Here, using the KrasG12D Trp53R172H Pdx1-Cre (KPC) mouse model of pancreatic ductal adenocarcinoma (PDAC), we show that deletion of Map4k4 drives tumour initiation and progression. Moreover, we report that the acceleration of tumour onset is also associated with an overactivation of ERK and AKT, two major downstream effectors of KRAS, in vitro and in vivo. In contrast to the accelerated tumour onset caused by loss of MAP4K4, we observed a reduction in metastatic burden with both the KPC model and in an intraperitoneal transplant assay indicating a major role of MAP4K4 in metastatic seeding. In summary, our study sheds light on the dichotomous role of MAP4K4 in the initiation of PDAC onset, progression, and metastatic dissemination. It also identifies MAP4K4 as a possible druggable target against pancreatic cancer spread, but with the caveat that targeting MAP4K4 might accelerate early tumorigenesis. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
    Keywords:  ERK and AKT signalling pathways; MAP4K4; invasion; metastatic seeding; pancreatic cancer; pancreatic intraepithelial neoplasia
    DOI:  https://doi.org/10.1002/path.6248
  3. Gut. 2024 Jan 17. pii: gutjnl-2023-330941. [Epub ahead of print]
      OBJECTIVE: Epidemiological studies highlight an association between pancreatic ductal adenocarcinoma (PDAC) and oral carriage of the anaerobic bacterium Porphyromonas gingivalis, a species highly linked to periodontal disease. We analysed the potential for P. gingivalis to promote pancreatic cancer development in an animal model and probed underlying mechanisms.DESIGN: We tracked P. gingivalis bacterial translocation from the oral cavity to the pancreas following administration to mice. To dissect the role of P. gingivalis in PDAC development, we administered bacteria to a genetically engineered mouse PDAC model consisting of inducible acinar cell expression of mutant Kras (Kras +/LSL-G12D; Ptf1a-CreER, iKC mice). These mice were used to study the cooperative effects of Kras mutation and P. gingivalis on the progression of pancreatic intraepithelial neoplasia (PanIN) to PDAC. The direct effects of P. gingivalis on acinar cells and PDAC cell lines were studied in vitro.
    RESULTS: P. gingivalis migrated from the oral cavity to the pancreas in mice and can be detected in human PanIN lesions. Repetitive P. gingivalis administration to wild-type mice induced pancreatic acinar-to-ductal metaplasia (ADM), and altered the composition of the intrapancreatic microbiome. In iKC mice, P. gingivalis accelerated PanIN to PDAC progression. In vitro, P. gingivalis infection induced acinar cell ADM markers SOX9 and CK19, and intracellular bacteria protected PDAC cells from reactive oxygen species-mediated cell death resulting from nutrient stress.
    CONCLUSION: Taken together, our findings demonstrate a causal role for P. gingivalis in pancreatic cancer development in mice.
    Keywords:  BACTERIAL INFECTION; PANCREATIC CANCER
    DOI:  https://doi.org/10.1136/gutjnl-2023-330941
  4. Nat Rev Cancer. 2024 Jan 18.
      Metastasis causes most cancer-related deaths; however, the efficacy of anti-metastatic drugs is limited by incomplete understanding of the biological mechanisms that drive metastasis. Focusing on the mechanics of metastasis, we propose that the ability of tumour cells to survive the metastatic process is enhanced by mechanical stresses in the primary tumour microenvironment that select for well-adapted cells. In this Perspective, we suggest that biophysical adaptations favourable for metastasis are retained via mechanical memory, such that the extent of memory is influenced by both the magnitude and duration of the mechanical stress. Among the mechanical cues present in the primary tumour microenvironment, we focus on high matrix stiffness to illustrate how it alters tumour cell proliferation, survival, secretion of molecular factors, force generation, deformability, migration and invasion. We particularly centre our discussion on potential mechanisms of mechanical memory formation and retention via mechanotransduction and persistent epigenetic changes. Indeed, we propose that the biophysical adaptations that are induced by this process are retained throughout the metastatic process to improve tumour cell extravasation, survival and colonization in the distant organ. Deciphering mechanical memory mechanisms will be key to discovering a new class of anti-metastatic drugs.
    DOI:  https://doi.org/10.1038/s41568-023-00656-5
  5. Matrix Biol Plus. 2023 Dec;19-20 100136
      High-grade serous (HGS) ovarian cancer is the most lethal gynaecological disease in the world and metastases is a major cause. The omentum is the preferential metastatic site in HGS ovarian cancer patients and in vitro models that recapitulate the original environment of this organ at cellular and molecular level are being developed to study basic mechanisms that underpin this disease. The tumour extracellular matrix (ECM) plays active roles in HGS ovarian cancer pathology and response to therapy. However, most of the current in vitro models use matrices of animal origin and that do not recapitulate the complexity of the tumour ECM in patients. Here, we have developed omentum gel (OmGel), a matrix made from tumour-associated omental tissue of HGS ovarian cancer patients that has unprecedented similarity to the ECM of HGS omental tumours and is simple to prepare. When used in 2D and 3D in vitro assays to assess cancer cell functions relevant to metastatic ovarian cancer, OmGel performs as well as or better than the widely use Matrigel and does not induce additional phenotypic changes to ovarian cancer cells. Surprisingly, OmGel promotes pronounced morphological changes in cancer associated fibroblasts (CAFs). These changes were associated with the upregulation of proteins that define subsets of CAFs in tumour patient samples, highlighting the importance of using clinically and physiologically relevant matrices for in vitro studies. Hence, OmGel provides a step forward to study the biology of HGS omental metastasis. Metastasis in the omentum are also typical of other cancer types, particularly gastric cancer, implying the relevance of OmGel to study the biology of other highly lethal cancers.
    Keywords:  CAF; Extracellular matrix; Matrisome; Omentum; Ovarian cancer
    DOI:  https://doi.org/10.1016/j.mbplus.2023.100136
  6. Phys Rev E. 2023 Dec;108(6-1): 064407
      Membrane curvature sensing is essential for a diverse range of biological processes. Recent experiments have revealed that a single nanometer-sized septin protein has different binding rates to membrane-coated glass beads of 1-µm and 3-µm diameters, even though the septin is orders of magnitude smaller than the beads. This sensing ability is especially surprising since curvature-sensing proteins must deal with persistent thermal fluctuations of the membrane, leading to discrepancies between the bead's curvature and the local membrane curvature sensed instantaneously by a protein. Using continuum models of fluctuating membranes, we investigate whether it is feasible for a protein acting as a perfect observer of the membrane to sense micron-scale curvature either by measuring local membrane curvature or by using bilayer lipid densities as a proxy. To do this, we develop algorithms to simulate lipid density and membrane shape fluctuations. We derive physical limits to the sensing efficacy of a protein in terms of protein size, membrane thickness, membrane bending modulus, membrane-substrate adhesion strength, and bead size. To explain the experimental protein-bead association rates, we develop two classes of predictive models: (i) for proteins that maximally associate to a preferred curvature and (ii) for proteins with enhanced association rates above a threshold curvature. We find that the experimentally observed sensing efficacy is close to the theoretical sensing limits imposed on a septin-sized protein. Protein-membrane association rates may depend on the curvature of the bead, but the strength of this dependence is limited by the fluctuations in membrane height and density.
    DOI:  https://doi.org/10.1103/PhysRevE.108.064407
  7. Biophys J. 2024 Jan 13. pii: S0006-3495(24)00004-3. [Epub ahead of print]
      Membrane curvature is ubiquitous and essential in cell biology. Curved membranes have several distinct features, including specific protein and lipid sorting, distinct lipid ordering, and changes in transbilayer stress. Curvature also interplays with membrane tension to generate forces that change membrane shape. This research highlight summarizes recent contributions to this topic published in Biophysical Journal.
    DOI:  https://doi.org/10.1016/j.bpj.2024.01.004
  8. Cancer Discov. 2024 Jan 18.
      KRASG12C inhibitors, like sotorasib and adagrasib, potently and selectively inhibit KRASG12C through a covalent interaction with the mutant cysteine, driving clinical efficacy in KRASG12C tumors. Since amino acid sequences of the three main RAS isoforms-KRAS, NRAS and HRAS-are highly similar, we hypothesized that some KRASG12C inhibitors might also target NRASG12C and/or HRASG12C, which are less common but critical oncogenic driver mutations in some tumors. While some inhibitors, like adagrasib, were highly selective for KRASG12C, others also potently inhibited NRASG12C and/or HRASG12C. Notably, sotorasib was 5-fold more potent against NRASG12C compared to KRASG12C or HRASG12C. Structural and reciprocal mutagenesis studies suggested that differences in isoform-specific binding are mediated by a single amino acid: Histidine-95 in KRAS (Leucine-95 in NRAS). A patient with NRASG12C colorectal cancer treated with sotorasib and the anti-EGFR antibody panitumumab achieved a marked tumor response, demonstrating that sotorasib can be clinically effective in NRASG12C-mutated tumors.
    DOI:  https://doi.org/10.1158/2159-8290.CD-23-1138
  9. Dev Cell. 2024 Jan 13. pii: S1534-5807(23)00691-3. [Epub ahead of print]
      During organ formation, progenitor cells need to acquire different cell identities and organize themselves into distinct structural units. How these processes are coordinated and how tissue architecture(s) is preserved despite the dramatic cell rearrangements occurring in developing organs remain unclear. Here, we identified cellular rearrangements between acinar and ductal progenitors as a mechanism to drive branching morphogenesis in the pancreas while preserving the integrity of the acinar-ductal functional unit. Using ex vivo and in vivo mouse models, we found that pancreatic ductal cells form clefts by protruding and pulling on the acinar basement membrane, which leads to acini splitting. Newly formed acini remain connected to the bifurcated branches generated by ductal cell rearrangement. Insulin growth factor (IGF)/phosphatidylinositol 3-kinase (PI3K) pathway finely regulates this process by controlling pancreatic ductal tissue fluidity, with a simultaneous impact on branching and cell fate acquisition. Together, our results explain how acinar structure multiplication and branch bifurcation are synchronized during pancreas organogenesis.
    Keywords:  ECM remodeling; IGF/PI3K; acinar-ductal architecture; branching morphogenesis; pancreas; pancreatic acinar cells; pancreatic ducts; tissue fluidity
    DOI:  https://doi.org/10.1016/j.devcel.2023.12.011
  10. J Cell Biochem. 2024 Jan 16.
      Small ubiquitin-like modifiers from the ATG8 family regulate autophagy initiation and progression in mammalian cells. Their interaction with LC3-interacting region (LIR) containing proteins promotes cargo sequestration, phagophore assembly, or even fusion between autophagosomes and lysosomes. Previously, we have shown that RabGAP proteins from the TBC family directly bind to LC3/GABARAP proteins. In the present study, we focus on the function of TBC1D2B. We show that TBC1D2B contains a functional canonical LIR motif and acts at an early stage of autophagy by binding to both LC3/GABARAP and ATG12 conjugation complexes. Subsequently, TBC1D2B is degraded by autophagy. TBC1D2B condensates into liquid droplets upon autophagy induction. Our study suggests that phase separation is an underlying mechanism of TBC1D2B-dependent autophagy induction.
    Keywords:  ATG8-related proteins; GTPase-activating protein; KIAA1055; autophagy; autophagy conjugation complex; liquid-liquid phase separation; phagophore formation
    DOI:  https://doi.org/10.1002/jcb.30481
  11. J Biol Chem. 2024 Jan 11. pii: S0021-9258(24)00021-8. [Epub ahead of print] 105645
      Glutathione (GSH) is a highly abundant tripeptide thiol that performs diverse protective and biosynthetic functions in cells. While changes in GSH availability are associated with inborn errors of metabolism, cancer and neurodegenerative disorders, studying the limiting role of GSH in physiology and disease has been challenging due to its tight regulation. To address this, we generated cell and mouse models that express a bifunctional glutathione-synthesizing enzyme from Streptococcus thermophilus (GshF), which possesses both glutamate-cysteine ligase and glutathione synthase activities. GshF expression allows efficient production of GSH in the cytosol and mitochondria and prevents cell death in response to GSH depletion, but not ferroptosis induction, indicating that GSH is not a limiting factor under lipid peroxidation. CRISPR screens using engineered enzymes further revealed genes required for cell proliferation under cellular and mitochondrial GSH depletion. Among these, we identified the glutamate-cysteine ligase modifier subunit, Gclm, as a requirement for cellular sensitivity to buthionine sulfoximne, a glutathione synthesis inhibitor. Finally, GshF expression in mice is embryonically lethal but sustains postnatal viability when restricted to adulthood. Overall, our work identifies a conditional mouse model to investigate the limiting role of GSH in physiology and disease.
    DOI:  https://doi.org/10.1016/j.jbc.2024.105645
  12. Lab Chip. 2024 Jan 19.
      The pancreatic ductal adenocarcinoma (PDAC) stroma and its inherent biophysical barriers to drug delivery are central to therapeutic resistance. This makes PDAC the most prevalent pancreatic cancer with poor prognosis. The chemotherapeutic drug gemcitabine is used against various solid tumours, including pancreatic cancer, but with only a modest effect on patient survival. The growing PDAC tumour mass with high densities of cells and extracellular matrix (ECM) proteins, i.e., collagen, results in high interstitial pressure, leading to vasculature collapse and a dense, hypoxic, mechanically stiff stroma with reduced interstitial flow, critical to drug delivery to cells. Despite this, most drug studies are performed on cellular models that neglect these biophysical barriers to drug delivery. Microfluidic technology offers a promising platform to emulate tumour biophysical characteristics with appropriate flow conditions and transport dynamics. We present a microfluidic PDAC culture model, encompassing the disease's biophysical barriers to therapeutics, to evaluate the use of the angiotensin II receptor blocker losartan, which has been found to have matrix-depleting properties, on improving gemcitabine efficacy. PDAC cells were seeded into our 5-channel microfluidic device for a 21-day culture to mimic the rigid, collagenous PDAC stroma with reduced interstitial flow, which is critical to drug delivery to the cancer cells, and for assessment with gemcitabine and losartan treatment. With losartan, our culture matrix was more porous with less collagen, resulting in increased hydraulic conductivity of the culture interstitial space and improved gemcitabine effect. We demonstrate the importance of modelling tumour biophysical barriers to successfully assess new drugs and delivery methods.
    DOI:  https://doi.org/10.1039/d3lc00660c
  13. Adv Healthc Mater. 2024 Jan 15. e2302436
      Microfluidic chips are valuable tools for studying intricate cellular and cell-microenvironment interactions. Traditional in vitro cancer models lack accuracy in mimicking the complexities of in vivo tumor microenvironment. However, cancer-metastasis-on-a-chip (CMoC) models combine the advantages of three dimensional (3D) cultures and microfluidic technology, serving as powerful platforms for exploring cancer mechanisms and facilitating drug screening. These chips are able to compartmentalize the metastatic cascade, deepening our understanding of its underlying mechanisms. This article provides an overview of current CMoC models, focusing on distinctive models that simulate invasion, intravasation, circulation, extravasation, and colonization, and their applications in drug screening. Furthermore, we discuss challenges faced by CMoC and microfluidic technologies, while exploring promising future directions in cancer research. The ongoing development and integration of these models into cancer studies are expected to drive transformative advancements in the field. This article is protected by copyright. All rights reserved.
    Keywords:  cancer-on-a-chip; drug screening; metastasis; microfluidics; tumor microenvironment
    DOI:  https://doi.org/10.1002/adhm.202302436
  14. Diabetes. 2024 Feb 01. 73(2): 162-168
      Physical activity confers systemic health benefits and provides powerful protection against disease. There has been tremendous interest in understanding the molecular effectors of exercise that mediate these physiologic effects. The modern growth of multiomics technologies-including metabolomics, proteomics, phosphoproteomics, lipidomics, single-cell RNA sequencing, and epigenomics-has provided unparalleled opportunities to systematically investigate the molecular changes associated with physical activity on an organism-wide scale. Here, we discuss how multiomics technologies provide new insights into the systemic effects of physical activity, including the integrative responses across organs as well as the molecules and mechanisms mediating tissue communication during exercise. We also highlight critical unanswered questions that can now be addressed using these high-dimensional tools and provide perspectives on fertile future research directions.
    DOI:  https://doi.org/10.2337/dbi23-0004
  15. Clin Epigenetics. 2024 Jan 16. 16(1): 13
      BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with poor prognosis. It is marked by extraordinary resistance to conventional therapies including chemotherapy and radiation, as well as to essentially all targeted therapies evaluated so far. More than 90% of PDAC cases harbor an activating KRAS mutation. As the most common KRAS variants in PDAC remain undruggable so far, it seemed promising to inhibit a downstream target in the MAPK pathway such as MEK1/2, but up to now preclinical and clinical evaluation of MEK inhibitors (MEKi) failed due to inherent and acquired resistance mechanisms. To gain insights into molecular changes during the formation of resistance to oncogenic MAPK pathway inhibition, we utilized short-term passaged primary tumor cells from ten PDACs of genetically engineered mice. We followed gain and loss of resistance upon MEKi exposure and withdrawal by longitudinal integrative analysis of whole genome sequencing, whole genome bisulfite sequencing, RNA-sequencing and mass spectrometry data.RESULTS: We found that resistant cell populations under increasing MEKi treatment evolved by the expansion of a single clone but were not a direct consequence of known resistance-conferring mutations. Rather, resistant cells showed adaptive DNA hypermethylation of 209 and hypomethylation of 8 genomic sites, most of which overlap with regulatory elements known to be active in murine PDAC cells. Both DNA methylation changes and MEKi resistance were transient and reversible upon drug withdrawal. Furthermore, MEKi resistance could be reversed by DNA methyltransferase inhibition with remarkable sensitivity exclusively in the resistant cells.
    CONCLUSION: Overall, the concept of acquired therapy resistance as a result of the expansion of a single cell clone with epigenetic plasticity sheds light on genetic, epigenetic and phenotypic patterns during evolvement of treatment resistance in a tumor with high adaptive capabilities and provides potential for reversion through epigenetic targeting.
    Keywords:  Cancer; Clonal expansion; DNA methylation; Epigenetic plasticity; PDAC; Therapy resistance; WGBS
    DOI:  https://doi.org/10.1186/s13148-024-01623-z
  16. Lancet Gastroenterol Hepatol. 2024 Jan 15. pii: S2468-1253(23)00405-3. [Epub ahead of print]
    Nordic Pancreatic Cancer Trial-1 study group
      BACKGROUND: In patients undergoing resection for pancreatic cancer, adjuvant modified fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) improves overall survival compared with alternative chemotherapy regimens. We aimed to compare the efficacy and safety of neoadjuvant FOLFIRINOX with the standard strategy of upfront surgery in patients with resectable pancreatic ductal adenocarcinoma.METHODS: NORPACT-1 was a multicentre, randomised, phase 2 trial done in 12 hospitals in Denmark, Finland, Norway, and Sweden. Eligible patients were aged 18 years or older, with a WHO performance status of 0 or 1, and had a resectable tumour of the pancreatic head radiologically strongly suspected to be pancreatic adenocarcinoma. Participants were randomly assigned (3:2 before October, 2018, and 1:1 after) to the neoadjuvant FOLFIRINOX group or upfront surgery group. Patients in the neoadjuvant FOLFIRINOX group received four neoadjuvant cycles of FOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 180 mg/m2, leucovorin 400 mg/m2, and fluorouracil 400 mg/m2 bolus then 2400 mg/m2 over 46 h on day 1 of each 14-day cycle), followed by surgery and adjuvant chemotherapy. Patients in the upfront surgery group underwent surgery and then received adjuvant chemotherapy. Initially, adjuvant chemotherapy was gemcitabine plus capecitabine (gemcitabine 1000 mg/m2 over 30 min on days 1, 8, and 15 of each 28-day cycle and capecitabine 830 mg/m2 twice daily for 3 weeks with 1 week of rest in each 28-day cycle; four cycles in the neoadjuvant FOLFIRINOX group, six cycles in the upfront surgery group). A protocol amendment was subsequently made to permit use of adjuvant modified FOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 150 mg/m2, leucovorin 400 mg/m2, and fluorouracil 2400 mg/m2 over 46 h on day 1 of each 14-day cycle; eight cycles in the neoadjuvant FOLFIRINOX group, 12 cycles in the upfront surgery group). Randomisation was performed with a computerised algorithm that stratified for each participating centre and used a concealed block size of two to six. Patients, investigators, and study team members were not masked to treatment allocation. The primary endpoint was overall survival at 18 months. Analyses were done in the intention-to-treat (ITT) and per-protocol populations. Safety was assessed in all patients who were randomly assigned and received at least one cycle of neoadjuvant or adjuvant therapy. This trial is registered with ClinicalTrials.gov, NCT02919787, and EudraCT, 2015-001635-21, and is ongoing.
    FINDINGS: Between Feb 8, 2017, and April 21, 2021, 77 patients were randomly assigned to receive neoadjuvant FOLFIRINOX and 63 to undergo upfront surgery. All patients were included in the ITT analysis. For the per-protocol analysis, 17 (22%) patients were excluded from the neoadjuvant FOLFIRINOX group (ten did not receive neoadjuvant therapy, four did not have pancreatic ductal adenocarcinoma, and three received another neoadjuvant regimen), and eight (13%) were excluded from the upfront surgery group (seven did not have pancreatic ductal adenocarcinoma and one did not undergo surgical exploration). 61 (79%) of 77 patients in the neoadjuvant FOLFIRINOX group received neoadjuvant therapy. The proportion of patients alive at 18 months by ITT was 60% (95% CI 49-71) in the neoadjuvant FOLFIRINOX group versus 73% (62-84) in the upfront surgery group (p=0·032), and median overall survival by ITT was 25·1 months (95% CI 17·2-34·9) versus 38·5 months (27·6-not reached; hazard ratio [HR] 1·52 [95% CI 1·00-2·33], log-rank p=0·050). The proportion of patients alive at 18 months in per-protocol analysis was 57% (95% CI 46-67) in the neoadjuvant FOLFIRINOX group versus 70% (55-83) in the upfront surgery group (p=0·14), and median overall survival in per-protocol population was 23·0 months (95% CI 16·2-34·9) versus 34·4 months (19·4-not reached; HR 1·46 [95% CI 0·99-2·17], log-rank p=0·058). In the safety population, 42 (58%) of 73 patients in the neoadjuvant FOLFIRINOX group and 19 (40%) of 47 patients in the upfront surgery group had at least one grade 3 or worse adverse event. 63 (82%) of 77 patients in the neoadjuvant group and 56 (89%) of 63 patients in the upfront surgery group had resection (p=0·24). One sudden death of unknown cause and one COVID-19-related death occurred after the first cycle of neoadjuvant FOLFIRINOX. Adjuvant chemotherapy was initiated in 51 (86%) of 59 patients with resected pancreatic ductal adenocarcinoma in the neoadjuvant FOLFIRINOX group and 44 (90%) of 49 patients with resected pancreatic ductal adenocarcinoma in the upfront surgery group (p=0·56). Adjuvant modified FOLFIRINOX was given to 13 (25%) patients in the neoadjuvant FOLFIRINOX group and 19 (43%) patients in the upfront surgery group. During adjuvant chemotherapy, neutropenia (11 [22%] patients in the neoadjuvant FOLFIRINOX group and five [11%] in the upfront surgery group) was the most common grade 3 or worse adverse event.
    INTERPRETATION: This phase 2 trial did not show a survival benefit from neoadjuvant FOLFIRINOX in resectable pancreatic ductal adenocarcinoma compared with upfront surgery. Implementation of neoadjuvant FOLFIRINOX was challenging. Future trials on treatment sequencing in resectable pancreatic ductal adenocarcinoma should be biomarker driven.
    FUNDING: Norwegian Cancer Society, South Eastern Norwegian Health Authority, The Sjöberg Foundation, and Helsinki University Hospital Research Grants.
    DOI:  https://doi.org/10.1016/S2468-1253(23)00405-3
  17. Cell Mol Life Sci. 2024 Jan 13. 81(1): 43
      Adherent cells ensure membrane homeostasis during de-adhesion by various mechanisms, including endocytosis. Although mechano-chemical feedbacks involved in this process have been studied, the step-by-step build-up and resolution of the mechanical changes by endocytosis are poorly understood. To investigate this, we studied the de-adhesion of HeLa cells using a combination of interference reflection microscopy, optical trapping and fluorescence experiments. We found that de-adhesion enhanced membrane height fluctuations of the basal membrane in the presence of an intact cortex. A reduction in the tether force was also noted at the apical side. However, membrane fluctuations reveal phases of an initial drop in effective tension followed by saturation. The area fractions of early (Rab5-labelled) and recycling (Rab4-labelled) endosomes, as well as transferrin-labelled pits close to the basal plasma membrane, also transiently increased. On blocking dynamin-dependent scission of endocytic pits, the regulation of fluctuations was not blocked, but knocking down AP2-dependent pit formation stopped the tension recovery. Interestingly, the regulation could not be suppressed by ATP or cholesterol depletion individually but was arrested by depleting both. The data strongly supports Clathrin and AP2-dependent pit-formation to be central to the reduction in fluctuations confirmed by super-resolution microscopy. Furthermore, we propose that cholesterol-dependent pits spontaneously regulate tension under ATP-depleted conditions.
    Keywords:  Excess area regulation; Membrane homeostasis; Tension propagation
    DOI:  https://doi.org/10.1007/s00018-023-05072-4
  18. Sci Rep. 2024 01 16. 14(1): 1408
      Leptin is an adipokine secreted by adipose tissue, which promotes tumor progression by activating canonical signaling pathways such as MAPK/ERK. Recent studies have shown that leptin induces autophagy, and this process is involved in leptin-induced characteristics of malignancy. Autophagy is an intracellular degradation process associated with different hallmarks of cancer, such as cell survival, migration, and metabolic reprogramming. However, its relationship with metabolic reprogramming has not been clearly described. The purpose of this study was to determine the role of leptin-induced autophagy in cancer cell metabolism and its association with cellular proliferation and migration in breast cancer cells. We used ER+/PR+ and triple-negative breast cancer cell lines treated with leptin, autophagy inhibition, or mitochondrial metabolism inhibitors. Our results show that leptin induces autophagy, increases proliferation, mitochondrial ATP production and mitochondrial function in ER+/PR+ cells. Importantly, autophagy was required to maintain metabolic changes and cell proliferation driven by leptin. In triple-negative cells, leptin did not induce autophagy or cell proliferation but increased glycolytic and mitochondrial ATP production, mitochondrial function, and cell migration. In triple negative cells, autophagy was required to support metabolic changes and cell migration, and autophagy inhibition decreased cellular migration similar to mitochondrial inhibitors. In conclusion, leptin-induced autophagy supports mitochondrial metabolism in breast cancer cells as well as glycolysis in triple negative cells. Importantly, leptin-induced mitochondrial metabolism promoted cancer cell migration.
    DOI:  https://doi.org/10.1038/s41598-024-51406-y
  19. J Clin Invest. 2024 Jan 18. pii: e166847. [Epub ahead of print]
      Cancer cell plasticity contributes to therapy resistance and metastasis, which represent the main causes of cancer-related death, including in breast cancer. The tumor microenvironment drives cancer cell plasticity and metastasis, and unravelling the underlying cues may provide novel strategies to manage metastatic disease. Using breast cancer experimental models and transcriptomic analyses, we showed that stem cell antigen-1 positive (SCA1+) murine breast cancer cells enriched during tumor progression and metastasis had higher in vitro cancer stem cell-like properties, enhanced in vivo metastatic ability, and generated tumors rich in Gr1high Ly6G+CD11b+ cells. In turn, tumor-educated Gr1+CD11b+(Tu-Gr1+CD11b+) cells rapidly and transiently converted low metastatic SCA1- cells into highly metastatic SCA1+ cells via secreted OSM and IL6. JAK inhibition prevented OSM/IL6-induced SCA1+ population enrichment while OSM/IL6 depletion suppressed Tu-Gr1+CD11b+-induced SCA1+ population enrichment in vitro and metastasis in vivo. Moreover, chemotherapy-selected highly metastatic 4T1 cells maintained high SCA1+ positivity through autocrine IL6 production and in vitro JAK inhibition blunted SCA1 positivity and metastatic capacity. Importantly, Tu-Gr1+CD11b+ cells invoked a gene signature in tumor cells predicting shorter OS, RFS and lung metastasis in breast cancer patients. Collectively, our data identified OSM/IL6-JAK as a clinically relevant paracrine/autocrine axis instigating breast cancer cell plasticity and triggering metastasis.
    Keywords:  Breast cancer; Oncology
    DOI:  https://doi.org/10.1172/JCI166847
  20. STAR Protoc. 2024 Jan 17. pii: S2666-1667(23)00778-5. [Epub ahead of print]5(1): 102811
      To investigate underlying mechanisms for cancer metastasis and promising therapies in animal models, spontaneous metastasis models can be used to recreate metastasis development. Here, we present three mouse models of spontaneous lung and/or liver metastasis induction. We describe steps for cancer cell preparation, mouse analgesia, and three injection techniques (subcutaneous, intracecal, and intramucosal). We then detail procedures for evaluating metastasis. Most of these models generate metastasis in a time span of 4 weeks in the majority of injected mice. For complete details on the use and execution of this protocol, please refer to Giannou et al.1.
    Keywords:  Cancer; Immunology; Model Organisms
    DOI:  https://doi.org/10.1016/j.xpro.2023.102811
  21. J Biol Chem. 2024 Jan 16. pii: S0021-9258(24)00025-5. [Epub ahead of print] 105649
      Class A G protein-coupled receptors (GPCRs), a superfamily of cell membrane signaling receptors, moonlight as constitutively active phospholipid scramblases. The plasma membrane of metazoan cells is replete with GPCRs, yet has a strong resting trans-bilayer phospholipid asymmetry, with the signaling lipid phosphatidylserine confined to the cytoplasmic leaflet. To account for the persistence of this lipid asymmetry in the presence of GPCR scramblases, we hypothesized that GPCR-mediated lipid scrambling is regulated by cholesterol, a major constituent of the plasma membrane. We now present a technique whereby synthetic vesicles reconstituted with GPCRs can be supplemented with cholesterol to a level similar to that of the plasma membrane and show that the scramblase activity of two prototypical GPCRs, opsin and the β1-adrenergic receptor, is impaired upon cholesterol loading. Our data suggest that cholesterol acts as a switch, inhibiting scrambling above a receptor-specific threshold concentration to disable GPCR scramblases at the plasma membrane.
    Keywords:  G protein‐coupled receptor (GPCR); cholesterol; fluorescence; liposome; membrane transporter reconstitution; phospholipid; plasma membrane; rhodopsin; scramblase; single particle profiling
    DOI:  https://doi.org/10.1016/j.jbc.2024.105649
  22. Genome Biol. 2024 Jan 15. 25(1): 17
      BACKGROUND: Deletion of haploinsufficient genes or duplication of triplosensitive ones results in phenotypic effects in a concentration-dependent manner, and the mechanisms underlying these dosage-sensitive effects remain elusive. Phase separation drives functional compartmentalization of biomolecules in a concentration-dependent manner as well, which suggests a potential link between these two processes, and warrants further systematic investigation.RESULTS: Here we provide bioinformatic and experimental evidence to show a close link between phase separation and dosage sensitivity. We first demonstrate that haploinsufficient or triplosensitive gene products exhibit a higher tendency to undergo phase separation. Assessing the well-established dosage-sensitive genes HNRNPK, PAX6, and PQBP1 with experiments, we show that these proteins undergo phase separation. Critically, pathogenic variations in dosage-sensitive genes disturb the phase separation process either through reduced protein levels, or loss of phase-separation-prone regions. Analysis of multi-omics data further demonstrates that loss-of-function genetic perturbations on phase-separating genes cause similar dysfunction phenotypes as dosage-sensitive gene perturbations. In addition, dosage-sensitive scores derived from population genetics data predict phase-separating proteins with much better performance than available sequence-based predictors, further illustrating close ties between these two parameters.
    CONCLUSIONS: Together, our study shows that phase separation is functionally linked to dosage sensitivity and provides novel insights for phase-separating protein prediction from the perspective of population genetics data.
    DOI:  https://doi.org/10.1186/s13059-023-03128-z
  23. Am J Transplant. 2024 Jan 12. pii: S1600-6135(24)00071-6. [Epub ahead of print]
    AST COTS MOuse MOdels in Transplantation (MOMOT) work group
      Mouse models have been instrumental for understanding mechanisms of transplant rejection and tolerance, but cross-study reproducibility and translation of experimental findings into effective clinical therapies are issues of concern. The MOuse MOdels in Transplantation (MOMOT) symposium gathered scientists and physician-scientists involved in basic and clinical research in transplantation to discuss the strengths and limitations of mouse transplant models and strategies to enhance their utility. Participants recognized that increased procedure standardization, and including use of prespecified, defined endpoints and statistical power analyses, would benefit the field. They also discussed the generation of new models that incorporate environmental and genetic variables affecting clinical outcomes as potentially important. If implemented, these strategies are expected to improve the reproducibility of mouse studies and increase their translation to clinical trials and, ideally, new FDA-approved drugs.
    DOI:  https://doi.org/10.1016/j.ajt.2024.01.006
  24. Cancer Discov. 2024 Jan 19.
      The limited efficacy of currently approved immunotherapies in EGFR-driven lung adenocarcinoma (LUAD) underscores the need to better understand alternative mechanisms governing local immunosuppression to fuel novel therapies. Elevated surfactant and GM-CSF secretion from the transformed epithelium induces tumor-associated alveolar macrophage (TA-AM) proliferation which supports tumor growth by rewiring inflammatory functions and lipid metabolism. TA-AM properties are driven by increased GM-CSF-PPARγ signaling and inhibition of airway GM-CSF or PPARγ in TA-AMs suppresses cholesterol efflux to tumor cells, which impairs EGFR phosphorylation and restrains LUAD progression. In the absence of TA-AM metabolic support, LUAD cells compensate by increasing cholesterol synthesis, and blocking PPARγ in TA-AMs simultaneous with statin therapy further suppresses tumor progression and increases proinflammatory immune responses. These results reveal new therapeutic combinations for immunotherapy resistant EGFR-mutant LUADs and demonstrate how cancer cells can metabolically co-opt TA-AMs through GM-CSF-PPARγ signaling to provide nutrients that promote oncogenic signaling and growth.
    DOI:  https://doi.org/10.1158/2159-8290.CD-23-0434
  25. J Cell Sci. 2024 Jan 15. pii: jcs261389. [Epub ahead of print]137(2):
      The actin cytoskeleton plays a critical role in cell architecture and the control of fundamental processes including cell division, migration and survival. The dynamics and organisation of F-actin have been widely studied in a breadth of cell types on classical two-dimensional (2D) surfaces. Recent advances in optical microscopy have enabled interrogation of these cytoskeletal networks in cells within three-dimensional (3D) scaffolds, tissues and in vivo. Emerging studies indicate that the dimensionality experienced by cells has a profound impact on the structure and function of the cytoskeleton, with cells in 3D environments exhibiting cytoskeletal arrangements that differ to cells in 2D environments. However, the addition of a third (and fourth, with time) dimension leads to challenges in sample preparation, imaging and analysis, necessitating additional considerations to achieve the required signal-to-noise ratio and spatial and temporal resolution. Here, we summarise the current tools for imaging actin in a 3D context and highlight examples of the importance of this in understanding cytoskeletal biology and the challenges and opportunities in this domain.
    Keywords:  3D imaging; Actin; Bioimage analysis; Cytoskeleton; Model organisms; Super-resolution microscopy
    DOI:  https://doi.org/10.1242/jcs.261389
  26. Sci Rep. 2024 01 17. 14(1): 1525
      The combination of oncogenes and tumor suppressors is involved in cancer development; however, it is still unknown whether their combination plays a critical role in cancer metastasis. We herein investigated whether genetic combinations affected cell migration ability by establishing the immortalized melanocytes, melan-a cells, with an oncogene, either BRAFV600E or GNA11Q209L, and the loss of mouse Pten. The loss of mouse Pten or human PTEN increased the cell migration ability of our established cells and human melanoma cell lines with oncogenic MAPK signaling and the BRAFV600E or NRASQ61R background, but not with the GNA11Q209L background or no oncogenes. Although increased migration was not related to PI3K-AKT activation, those migration is regulated by the induction of some components in the WAVE regulatory complex, resulting in a higher rate of the formation of lamellipodia. On the other hand, BRAFV600E induced EphA2 phosphorylation at serine 897 through RSK and was also required for cell migration and the formation of lamellipodia. Therefore, the oncogenic MAPK pathway and loss of Pten in melanoma were important for cell migration through the formation of lamellipodia, suggesting the significance of an appropriate combination of genetic alterations not only in cancer development, but also cancer metastasis.
    DOI:  https://doi.org/10.1038/s41598-024-52020-8
  27. Microscopy (Oxf). 2024 Jan 12. pii: dfad064. [Epub ahead of print]
      Intracellular organelles alter their morphology in response to ambient conditions such as temperature to optimize physiological activities in cells. Observing organelle dynamics at various temperatures deepens our understanding of cellular responses to the environment. Confocal laser microscopy is a powerful tool for live-cell imaging of fluorescently labeled organelles. However, the large contact area between the specimen and the ambient air on the microscope stage makes it difficult to maintain accurate cellular temperatures. Here, we present a method for precisely controlling cellular temperatures using a custom-made adaptor that can be installed on a commercially available temperature-controlled microscope stage. Using this adaptor, we observed temperature-dependent organelle dynamics in living plant cells; morphological changes in chloroplasts and peroxisomes were temperature dependent. This newly developed adaptor can easily be placed on a temperature-controlled stage to capture intracellular responses to temperature at unprecedentedly high resolution.
    Keywords:  Confocal laser-scanning microscopy; microscope stage; organellar dynamics; organellar morphology; peroxisome; temperature control
    DOI:  https://doi.org/10.1093/jmicro/dfad064
  28. Elife. 2024 Jan 19. pii: e85214. [Epub ahead of print]13
      Lysosomes are active sites to integrate cellular metabolism and signal transduction. A collection of proteins associated with the lysosome mediate these metabolic and signaling functions. Both lysosomal metabolism and lysosomal signaling have been linked to longevity regulation; however, how lysosomes adjust their protein composition to accommodate this regulation remains unclear. Using deep proteomic profiling, we systemically profiled lysosome-associated proteins linked with four different longevity mechanisms. We discovered the lysosomal recruitment of AMPK and nucleoporin proteins and their requirements for longevity in response to increased lysosomal lipolysis. Through comparative proteomic analyses of lysosomes from different tissues and labeled with different markers, we further elucidated lysosomal heterogeneity across tissues as well as the increased enrichment of the Ragulator complex on Cystinosin positive lysosomes. Together, this work uncovers lysosomal proteome heterogeneity across multiple scales and provides resources for understanding the contribution of lysosomal protein dynamics to signal transduction, organelle crosstalk and organism longevity.
    Keywords:  C. elegans; cell biology
    DOI:  https://doi.org/10.7554/eLife.85214
  29. Nat Genet. 2024 Jan 19.
      Understanding why we age is a long-standing question, and many mechanistic theories of aging have been proposed. Owing to limitations in studying the aging process, including a lack of adequate quantitative measurements, its mechanistic basis remains a subject of debate. Here, I explore theories of aging from the perspective of causal relationships. Many aging-related changes have been observed and touted as drivers of aging, including molecular changes in the genome, telomeres, mitochondria, epigenome and proteins and cellular changes affecting stem cells, the immune system and senescent cell buildup. Determining which changes are drivers and not passengers of aging remains a challenge, however, and I discuss how animal models and human genetic studies have been used empirically to infer causality. Overall, our understanding of the drivers of human aging is still inadequate; yet with a global aging population, elucidating the causes of aging has the potential to revolutionize biomedical research.
    DOI:  https://doi.org/10.1038/s41588-023-01627-0
  30. J Cell Sci. 2024 Jan 15. pii: jcs261898. [Epub ahead of print]137(2):
      Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases that belong to the group of endopeptidases or matrixins. They are able to cleave a plethora of substrates, including components of the extracellular matrix and cell-surface-associated proteins, as well as intracellular targets. Accordingly, MMPs play key roles in a variety of physiological and pathological processes, such as tissue homeostasis and cancer cell invasion. MMP activity is exquisitely regulated at several levels, including pro-domain removal, association with inhibitors, intracellular trafficking and transport via extracellular vesicles. Moreover, the regulation of MMP activity is currently being rediscovered for the development of respective therapies for the treatment of cancer, as well as infectious, inflammatory and neurological diseases. In this Cell Science at a Glance article and the accompanying poster, we present an overview of the current knowledge regarding the regulation of MMP activity, the intra- and extra-cellular trafficking pathways of these enzymes and their diverse groups of target proteins, as well as their impact on health and disease.
    Keywords:  Cell invasion; Intracellular trafficking; Invadosomes; Matrix metalloproteinases; Motor proteins; Proteolysis; Rab GTPases
    DOI:  https://doi.org/10.1242/jcs.261898