bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2021‒05‒02
sixty-four papers selected by
Kıvanç Görgülü
Technical University of Munich

  1. Cell Stem Cell. 2021 Apr 21. pii: S1934-5909(21)00155-7. [Epub ahead of print]
      The exocrine pancreas, consisting of ducts and acini, is the site of origin of pancreatitis and pancreatic ductal adenocarcinoma (PDAC). Our understanding of the genesis and progression of human pancreatic diseases, including PDAC, is limited because of challenges in maintaining human acinar and ductal cells in culture. Here we report induction of human pluripotent stem cells toward pancreatic ductal and acinar organoids that recapitulate properties of the neonatal exocrine pancreas. Expression of the PDAC-associated oncogene GNASR201C induces cystic growth more effectively in ductal than acinar organoids, whereas KRASG12D is more effective in modeling cancer in vivo when expressed in acinar compared with ductal organoids. KRASG12D, but not GNASR201C, induces acinar-to-ductal metaplasia-like changes in culture and in vivo. We develop a renewable source of ductal and acinar organoids for modeling exocrine development and diseases and demonstrate lineage tropism and plasticity for oncogene action in the human pancreas.
    Keywords:  GNAS; KRAS; acini; cancer precursor; exocrine pancreas; lineage specification; organoid; pancreatic cancer; plasticity; pluripotent stem cell
  2. Nat Cancer. 2021 Mar;2(3): 258-270
      The systemic spread of tumor cells is the ultimate cause of the majority of deaths from cancer, yet few successful therapeutic strategies have emerged to specifically target metastasis. Here we discuss recent advances in our understanding of tumor-intrinsic pathways driving metastatic colonization and therapeutic resistance, as well as immune activating strategies to target metastatic disease. We focus on therapeutically exploitable mechanisms, promising strategies in preclinical and clinical development, and emerging areas with potential to become innovative treatments.
  3. Nat Metab. 2021 Apr 26.
      Cytosolic mitochondrial DNA (mtDNA) elicits a type I interferon response, but signals triggering the release of mtDNA from mitochondria remain enigmatic. Here, we show that mtDNA-dependent immune signalling via the cyclic GMP-AMP synthase‒stimulator of interferon genes‒TANK-binding kinase 1 (cGAS-STING-TBK1) pathway is under metabolic control and is induced by cellular pyrimidine deficiency. The mitochondrial protease YME1L preserves pyrimidine pools by supporting de novo nucleotide synthesis and by proteolysis of the pyrimidine nucleotide carrier SLC25A33. Deficiency of YME1L causes inflammation in mouse retinas and in cultured cells. It drives the release of mtDNA and a cGAS-STING-TBK1-dependent inflammatory response, which requires SLC25A33 and is suppressed upon replenishment of cellular pyrimidine pools. Overexpression of SLC25A33 is sufficient to induce immune signalling by mtDNA. Similarly, depletion of cytosolic nucleotides upon inhibition of de novo pyrimidine synthesis triggers mtDNA-dependent immune responses in wild-type cells. Our results thus identify mtDNA release and innate immune signalling as a metabolic response to cellular pyrimidine deficiencies.
  4. Cell Metab. 2021 Apr 22. pii: S1550-4131(21)00168-6. [Epub ahead of print]
      Altered tissue mechanics and metabolism are defining characteristics of cancer that impact not only proliferation but also migration. While migrating through a mechanically and spatially heterogeneous microenvironment, changes in metabolism allow cells to dynamically tune energy generation and bioenergetics in response to fluctuating energy needs. Physical cues from the extracellular matrix influence mechanosignaling pathways, cell mechanics, and cytoskeletal architecture to alter presentation and function of metabolic enzymes. In cancer, altered mechanosensing and metabolic reprogramming supports metabolic plasticity and high energy production while cells migrate and metastasize. Here, we discuss the role of mechanoresponsive metabolism in regulating cell migration and supporting metastasis as well as the potential of therapeutically targeting cancer metabolism to block motility and potentially metastasis.
    Keywords:  bioenergetics; cancer invasion; energy metabolism; mechanotransduction; tumor microenvironment
  5. Nat Biotechnol. 2021 Apr 29.
      Because of the stochasticity associated with high-throughput single-cell sequencing, current methods for exploring cell-type diversity rely on clustering-based computational approaches in which heterogeneity is characterized at cell subpopulation rather than at full single-cell resolution. Here we present Cell-ID, a clustering-free multivariate statistical method for the robust extraction of per-cell gene signatures from single-cell sequencing data. We applied Cell-ID to data from multiple human and mouse samples, including blood cells, pancreatic islets and airway, intestinal and olfactory epithelium, as well as to comprehensive mouse cell atlas datasets. We demonstrate that Cell-ID signatures are reproducible across different donors, tissues of origin, species and single-cell omics technologies, and can be used for automatic cell-type annotation and cell matching across datasets. Cell-ID improves biological interpretation at individual cell level, enabling discovery of previously uncharacterized rare cell types or cell states. Cell-ID is distributed as an open-source R software package.
  6. Antioxidants (Basel). 2021 Apr 15. pii: 609. [Epub ahead of print]10(4):
      Mitochondria are popularly called the "powerhouses" of the cell. They promote energy metabolism through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, which in contrast to cytosolic glycolysis are oxygen-dependent and significantly more substrate efficient. That is, mitochondrial metabolism provides substantially more cellular energy currency (ATP) per macronutrient metabolised. Enhancement of mitochondrial density and metabolism are associated with endurance training, which allows for the attainment of high relative VO2 max values. However, the sedentary lifestyle and diet currently predominant in the Western world lead to mitochondrial dysfunction. Underdeveloped mitochondrial metabolism leads to nutrient-induced reducing pressure caused by energy surplus, as reduced nicotinamide adenine dinucleotide (NADH)-mediated high electron flow at rest leads to "electron leak" and a chronic generation of superoxide radicals (O2-). Chronic overload of these reactive oxygen species (ROS) damages cell components such as DNA, cell membranes, and proteins. Counterintuitively, transiently generated ROS during exercise contributes to adaptive reduction-oxidation (REDOX) signalling through the process of cellular hormesis or "oxidative eustress" defined by Helmut Sies. However, the unaccustomed, chronic oxidative stress is central to the leading causes of mortality in the 21st century-metabolic syndrome and the associated cardiovascular comorbidities. The endurance exercise training that improves mitochondrial capacity and the protective antioxidant cellular system emerges as a universal intervention for mitochondrial dysfunction and resultant comorbidities. Furthermore, exercise might also be a solution to prevent ageing-related degenerative diseases, which are caused by impaired mitochondrial recycling. This review aims to break down the metabolic components of exercise and how they translate to athletic versus metabolically diseased phenotypes. We outline a reciprocal relationship between oxidative metabolism and inflammation, as well as hypoxia. We highlight the importance of oxidative stress for metabolic and antioxidant adaptation. We discuss the relevance of lactate as an indicator of critical exercise intensity, and inferring from its relationship with hypoxia, we suggest the most appropriate mode of exercise for the case of a lost oxidative identity in metabolically inflexible patients. Finally, we propose a reciprocal signalling model that establishes a healthy balance between the glycolytic/proliferative and oxidative/prolonged-ageing phenotypes. This model is malleable to adaptation with oxidative stress in exercise but is also susceptible to maladaptation associated with chronic oxidative stress in disease. Furthermore, mutations of components involved in the transcriptional regulatory mechanisms of mitochondrial metabolism may lead to the development of a cancerous phenotype, which progressively presents as one of the main causes of death, alongside the metabolic syndrome.
    Keywords:  endurance exercise; metabolic disease; oxidative phenotype; oxidative stress
  7. Cancer Res. 2021 Apr 26. pii: canres.CAN-20-4263-E.2020. [Epub ahead of print]
      Activating mutations in some isoforms of Ras or Raf are drivers of a substantial proportion of cancers. The main Raf effector, Mek1/2, can be targeted with several highly specific inhibitors. The clinical activity of these inhibitors seems to be mixed, showing efficacy against mutant BRAF-driven tumors but not K-Ras-driven tumors, such as pancreatic adenocarcinomas. To improve our understanding of this context-dependent efficacy, we generated pancreatic cancer cells resistant to Mek1/2 inhibition, which were also resistant to KRAS and Erk1/2 inhibitors. Compared to parental cells, inhibitor-resistant cells showed several phenotypic changes including increased metastatic ability in vivo. The transcription factor Slug, which is known to induce epithelial-to-mesenchymal transition (EMT), was identified as the key factor responsible for both resistance to Mek1/2 inhibition and increased metastasis. Slug, but not similar transcription factors, predicted poor prognosis of pancreatic cancer patients and induced the transition to a cellular phenotype in which cell cycle progression becomes independent of the KRAS-Raf-Mek1/2-Erk1/2 pathway. Slug was targeted using two independent strategies: i) inhibition of the Mek5-Erk5 pathway, which is responsible for upregulation of Slug upon Mek1/2 inhibition, and ii) direct PROTAC-mediated degradation. Both strategies were efficacious in preclinical pancreatic cancer models, paving the path for the development of more effective therapies against pancreatic cancer.
  8. Metabolites. 2021 Apr 28. pii: 279. [Epub ahead of print]11(5):
      Ketogenesis occurs in liver mitochondria where acetyl-CoA molecules, derived from lipid oxidation, are condensed into acetoacetate (AcAc) and reduced to β-hydroxybutyrate (BHB). During carbohydrate scarcity, these two ketones are released into circulation at high rates and used as oxidative fuels in peripheral tissues. Despite their physiological relevance and emerging roles in a variety of diseases, endogenous ketone production is rarely measured in vivo using tracer approaches. Accurate determination of this flux requires a two-pool model, simultaneous BHB and AcAc tracers, and special consideration for the stability of the AcAc tracer and analyte. We describe the implementation of a two-pool model using a metabolic flux analysis (MFA) approach that simultaneously regresses liquid chromatography-tandem mass spectrometry (LC-MS/MS) ketone isotopologues and tracer infusion rates. Additionally, 1H NMR real-time reaction monitoring was used to evaluate AcAc tracer and analyte stability during infusion and sample analysis, which were critical for accurate flux calculations. The approach quantifies AcAc and BHB pool sizes and their rates of appearance, disposal, and exchange. Regression analysis provides confidence intervals and detects potential errors in experimental data. Complications for the physiological interpretation of individual ketone fluxes are discussed.
    Keywords:  13C MFA; 1H NMR; BHB; LC-MS/MS; acetoacetate; flux; in vivo; ketogenesis; liver; metabolism; metabolomics; stable isotope
  9. Mol Cell. 2021 Apr 21. pii: S1097-2765(21)00232-X. [Epub ahead of print]
      Aberrant energy status contributes to multiple metabolic diseases, including obesity, diabetes, and cancer, but the underlying mechanism remains elusive. Here, we report that ketogenic-diet-induced changes in energy status enhance the efficacy of anti-CTLA-4 immunotherapy by decreasing PD-L1 protein levels and increasing expression of type-I interferon (IFN) and antigen presentation genes. Mechanistically, energy deprivation activates AMP-activated protein kinase (AMPK), which in turn, phosphorylates PD-L1 on Ser283, thereby disrupting its interaction with CMTM4 and subsequently triggering PD-L1 degradation. In addition, AMPK phosphorylates EZH2, which disrupts PRC2 function, leading to enhanced IFNs and antigen presentation gene expression. Through these mechanisms, AMPK agonists or ketogenic diets enhance the efficacy of anti-CTLA-4 immunotherapy and improve the overall survival rate in syngeneic mouse tumor models. Our findings reveal a pivotal role for AMPK in regulating the immune response to immune-checkpoint blockade and advocate for combining ketogenic diets or AMPK agonists with anti-CTLA4 immunotherapy to combat cancer.
    Keywords:  AMPK; CMTM4; CTLA-4; EZH2; PD-L1; energy stress; glucose; immune checkpoint; ketogenic diet; phosphorylation
  10. J Physiol. 2021 Apr 24.
      KEY POINTS: Ageing is associated with increased systemic inflammation and metabolic dysfunction that contributes to the development of age-associated diseases. The role of adipose tissue in immunometabolic alterations that take place with ageing is unknown in humans. We show in healthy, active and lean older adults that adipose tissue-but not skeletal muscle-displays considerable pro-inflammatory transcriptomic, cellular, and secretory changes, and a reduction in insulin signalling proteins compared to younger adults. These findings indicate that adipose tissue undergoes substantial immunometabolic alterations with ageing, and that these changes are tissue-specific and more profound than those observed in skeletal muscle or in the circulation. These results identify adipose tissue as an important tissue in the biological ageing process in humans, which may exhibit signs of immunometabolic dysfunction prior to systemic manifestation.ABSTRACT: Ageing and obesity are both characterised by inflammation and a deterioration in metabolic health. It is now clear that adipose tissue plays a major role in inflammation and metabolic control in obesity, but little is known about the role of adipose tissue in human ageing. To understand how ageing impacts adipose tissue, we characterised subcutaneous adipose and skeletal muscle samples from twelve Young (27 ± 4yrs) and twelve Old (66 ± 5yrs) active/ non-obese adults. We performed a wide-range of whole-body and tissue measures, including RNA-sequencing and multi-colour flow cytometry. We also measured a range of inflammatory and metabolic proteins in the circulation and their release by adipose tissue, ex vivo. Both adipose tissue and muscle had ∼2-fold more immune cells per gram of tissue with ageing. In adipose tissue, this immune cell infiltration was driven by increased memory/ effector T-cells, whereas in muscle the accumulation was driven by memory/ effector T-cells and macrophages. Transcriptomic analysis revealed that, with ageing, adipose tissue-but not muscle-was enriched for inflammatory transcripts/ pathways related to acquired and innate immunity. Ageing also increased the adipose tissue pro-inflammatory secretory profile. Insulin signalling protein content was reduced in adipose tissue, but not muscle. Our findings indicate that adipose tissue undergoes substantial immunometabolic changes with ageing in humans, and that these changes are tissue-specific and more profound than those observed in the circulation and skeletal muscle. This article is protected by copyright. All rights reserved.
    Keywords:  adipose tissue; aging; immunometabolism; inflammation; metabolism; skeletal muscle
  11. Cancers (Basel). 2021 Apr 13. pii: 1852. [Epub ahead of print]13(8):
      Oncogenic mutations in RAS family genes arise frequently in metastatic human cancers. Here we developed new mouse and cellular models of oncogenic HrasG12V-driven undifferentiated pleomorphic sarcoma metastasis and of KrasG12D-driven pancreatic ductal adenocarcinoma metastasis. Through analyses of these cells and of human oncogenic KRAS-, NRAS- and BRAF-driven cancer cell lines we identified that resistance to single MEK inhibitor and ERK inhibitor treatments arise rapidly but combination therapy completely blocks the emergence of resistance. The prior evolution of resistance to either single agent frequently leads to resistance to dual treatment. Dual MEK inhibitor plus ERK inhibitor therapy shows anti-tumor efficacy in an HrasG12V-driven autochthonous sarcoma model but features of drug resistance in vivo were also evident. Array-based kinome activity profiling revealed an absence of common patterns of signaling rewiring in single or double MEK and ERK inhibitor resistant cells, showing that the development of resistance to downstream signaling inhibition in oncogenic RAS-driven tumors represents a heterogeneous process. Nonetheless, in some single and double MEK and ERK inhibitor resistant cell lines we identified newly acquired drug sensitivities. These may represent additional therapeutic targets in oncogenic RAS-driven tumors and provide general proof-of-principle that therapeutic vulnerabilities of drug resistant cells can be identified.
    Keywords:  ERK inhibitor; MEK inhibitor; drug resistance; metastasis; mouse tumor model; oncogenic RAS; pancreatic ductal adenocarcinoma; undifferentiated pleomorphic sarcoma
  12. Mol Oncol. 2021 May 01.
      Pancreatic acinar cells have high plasticity and can transdifferentiate into ductal-like cells. This acinar-to-ductal metaplasia (ADM) contributes to tissue maintenance but may also contribute to the premalignant transformation that can eventually progress to pancreatic ductal adenocarcinoma (PDAC). Macrophages are key players in ADM, and macrophage secreted matrix metalloproteinase (MMP)-9 induces ADM through yet unknown mechanisms. As we previously identified MMP9 as a novel agonist of protease-activated receptor 1 (PAR1), a receptor that is known to orchestrate the cross-talk between macrophages and tumor cells in PDAC, we here assessed the contribution of PAR1 to pancreatic cell fates. We found that genetic deficiency for PAR1 increases acinar gene expression programs in the healthy pancreas and that PAR1 deficiency limits ductal transdifferentiation in experimental systems for ADM. Moreover, PAR1 silencing in PDAC cells increases acinar marker expression. Changes in PDAC cell lines were associated with a downregulation of known Myc-target genes, and Myc inhibition mimics PAR1 deficiency in enhancing acinar programs in healthy organoids and PDAC cells. Overall, we identify the PAR1-Myc axis as a driver of ductal cell fates in premalignant pancreas and PDAC. Moreover, we show that cellular plasticity is not unique to acinar cells and that ductal regeneration into acinar-like cells is possible even in the context of oncogenic KRAS activation.
    Keywords:  Myc; PDAC; Protease-activated receptor 1; acinar-to-ductal metaplasia
  13. Proc Natl Acad Sci U S A. 2021 May 04. pii: e2101027118. [Epub ahead of print]118(18):
      Aberrant Ras signaling is linked to a wide spectrum of hyperproliferative diseases, and components of the signaling pathway, including Ras, have been the subject of intense and ongoing drug discovery efforts. The cellular activity of Ras is modulated by its association with the guanine nucleotide exchange factor Son of sevenless (Sos), and the high-resolution crystal structure of the Ras-Sos complex provides a basis for the rational design of orthosteric Ras ligands. We constructed a synthetic Sos protein mimic that engages the wild-type and oncogenic forms of nucleotide-bound Ras and modulates downstream kinase signaling. The Sos mimic was designed to capture the conformation of the Sos helix-loop-helix motif that makes critical contacts with Ras in its switch region. Chemoproteomic studies illustrate that the proteomimetic engages Ras and other cellular GTPases. The synthetic proteomimetic resists proteolytic degradation and enters cells through macropinocytosis. As such, it is selectively toxic to cancer cells with up-regulated macropinocytosis, including those that feature oncogenic Ras mutations.
    Keywords:  Ras; Sos; peptide; proteomimetic
  14. Cells. 2021 Apr 08. pii: 847. [Epub ahead of print]10(4):
      Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with a 5 year survival rate of less than 8%, and is predicted to become the second leading cause of cancer-related death by 2030. Alongside late detection, which impacts upon surgical treatment, PDAC tumours are challenging to treat due to their desmoplastic stroma and hypovascular nature, which limits the effectiveness of chemotherapy and radiotherapy. Pancreatic stellate cells (PSCs), which form a key part of this stroma, become activated in response to tumour development, entering into cross-talk with cancer cells to induce tumour cell proliferation and invasion, leading to metastatic spread. We and others have shown that Fibroblast Growth Factor Receptor (FGFR) signalling can play a critical role in the interactions between PDAC cells and the tumour microenvironment, but it is clear that the FGFR signalling pathway is not acting in isolation. Here we describe our current understanding of the mechanisms by which FGFR signalling contributes to PDAC progression, focusing on its interaction with other pathways in signalling networks and discussing the therapeutic approaches that are being developed to try and improve prognosis for this terrible disease.
    Keywords:  FGF signalling; crosstalk; pancreatic cancer; stroma; targeted therapy
  15. Mol Cancer Res. 2021 Apr 30. pii: molcanres.0633.2020. [Epub ahead of print]
      Pancreatic cancer is characterized by aberrant activity of oncogenic KRAS, which is mutated in 90% of pancreatic adenocarcinomas. Since KRAS itself is a challenging therapeutic target, we focused on understanding key signaling pathways driven by KRAS as a way to reveal dependencies that are amenable to therapeutic intervention. Analyses in primary human pancreatic cancers and model systems revealed that the receptor for the cytokine leukemia inhibitory factor (LIF) is down-regulated by mutant KRAS. Furthermore, down-regulation of the LIF receptor (LIFR) is necessary for KRAS-mediated neoplastic transformation. We found LIFR exerts inhibitory effects on KRAS-mediated transformation by inhibiting expression of the glucose transporter GLUT1, a key mediator of the enhanced glycolysis found in KRAS-driven malignancies. Decreased LIFR expression leads to increased GLUT1 as well as increases in glycolysis and mitochondrial respiration. The repression of GLUT1 by LIFR is mediated by the transcription factor STAT3, indicating a tumor suppressive role for STAT3 within cancer cells with mutated KRAS. Finally, reflecting a clinically important tumor suppressive role of LIFR, decreased LIFR expression correlates with shorter survival in pancreatic cancer patients with mutated KRAS. Similar findings were found in non-small cell lung cancers driven by mutated KRAS, suggesting that silencing LIFR is a generalized mechanism of KRAS-mediated cellular transformation. These results indicate that the LIFR/STAT3 pathway may mediate either tumor promoting or tumor suppressive signaling pathways depending on the genetic background of tumor cells, and may play diverse roles within other cells in the tumor microenvironment. Implications: Mutant KRAS drives downregulation of the receptor for leukemia inhibitory factor, thereby allowing an increase in expression of the glucose transporter GLUT1 and increases in glycolysis and mitochondrial respiration.
  16. Trends Cancer. 2021 Apr 22. pii: S2405-8033(21)00081-9. [Epub ahead of print]
      The mitochondrial electron transport chain (ETC) has been an attractive target for cancer therapy due to its essentiality for tumor growth. Krall et al. found that under ETC dysfunction, a decrease in asparagine limits cancer cell proliferation and activates the integrated stress response, creating a therapeutically exploitable metabolic vulnerability.
  17. Elife. 2021 04 27. pii: e59809. [Epub ahead of print]10
      Oncogenes often promote cell death as well as proliferation. How oncogenes drive these diametrically opposed phenomena remains to be solved. A key question is whether cell death occurs as a response to aberrant proliferation signals or through a proliferation-independent mechanism. Here, we reveal that Src, the first identified oncogene, simultaneously drives cell proliferation and death in an obligatorily coupled manner through parallel MAPK pathways. The two MAPK pathways diverge from a lynchpin protein Slpr. A MAPK p38 drives proliferation whereas another MAPK JNK drives apoptosis independently of proliferation signals. Src-p38-induced proliferation is regulated by methionine-mediated Tor signaling. Reduction of dietary methionine uncouples the obligatory coupling of cell proliferation and death, suppressing tumorigenesis and tumor-induced lethality. Our findings provide an insight into how cells evolved to have a fail-safe mechanism that thwarts tumorigenesis by the oncogene Src. We also exemplify a diet-based approach to circumvent oncogenesis by exploiting the fail-safe mechanism.
    Keywords:  D. melanogaster; cancer biology; cell death; methionine; nutrition; oncogene; proliferation
  18. Membranes (Basel). 2021 Apr 28. pii: 323. [Epub ahead of print]11(5):
      Although liquid-liquid phase separation of cytoplasmic or nuclear components in cells has been a major focus in cell biology, it is only recently that the principle of phase separation has been a long-standing concept and extensively studied in biomembranes. Membrane phase separation has been reconstituted in simplified model systems, and its detailed physicochemical principles, including essential phase diagrams, have been extensively explored. These model membrane systems have proven very useful to study the heterogeneity in cellular membranes, however, concerns have been raised about how reliably they can represent native membranes. In this review, we will discuss how phase-separated membrane systems can mimic cellular membranes and where they fail to reflect the native cell membrane heterogeneity. We also include a few humble suggestions on which phase-separated systems should be used for certain applications, and which interpretations should be avoided to prevent unreliable conclusions.
    Keywords:  GPMVs; GUVs; SLBs; lipid rafts; liquid-disordered domains; liquid-ordered domains; phase separation; plasma membrane; plasma membrane vesicles
  19. Cancers (Basel). 2021 Apr 20. pii: 1971. [Epub ahead of print]13(8):
      Pancreatic ductal adenocarcinoma (PDAC) represents an aggressive tumor of the digestive system with still low five-year survival of less than 10%. Although there are improvements for multimodal therapy of PDAC, surgery still remains the effective way to treat the disease. Combined with adjuvant and/or neoadjuvant treatment, pancreatic surgery is able to enhance the five-year survival up to around 20%. However, pancreatic resection is always associated with a high risk of complications and regarded as one of the most complex fields in abdominal surgery. This review gives a summary on the surgical treatment for PDAC based on the current literature with a special focus on resection techniques.
    Keywords:  pancreatic ductal adenocarcinoma; surgical treatment; technical advances
  20. Cancer Metab. 2021 Apr 30. 9(1): 20
      Pyruvate carboxylase (PC) is a mitochondrial enzyme that catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate (OAA), serving to replenish the tricarboxylic acid (TCA) cycle. In nonmalignant tissue, PC plays an essential role in controlling whole-body energetics through regulation of gluconeogenesis in the liver, synthesis of fatty acids in adipocytes, and insulin secretion in pancreatic β cells. In breast cancer, PC activity is linked to pulmonary metastasis, potentially by providing the ability to utilize glucose, fatty acids, and glutamine metabolism as needed under varying conditions as cells metastasize. PC enzymatic activity appears to be of particular importance in cancer cells that are unable to utilize glutamine for anaplerosis. Moreover, PC activity also plays a role in lipid metabolism and protection from oxidative stress in cancer cells. Thus, PC activity may be essential to link energy substrate utilization with cancer progression and to enable the metabolic flexibility necessary for cell resilience to changing and adverse conditions during the metastatic process.
    Keywords:  Energy metabolism; Metastasis; Pyruvate carboxylase
  21. Dev Cell. 2021 Apr 27. pii: S1534-5807(21)00317-8. [Epub ahead of print]
      Cellular senescence is a complex stress response implicated in aging. Autophagy can suppress senescence but is counterintuitively necessary for full senescence. Although its anti-senescence role is well described, to what extent autophagy contributes to senescence establishment and the underlying mechanisms is poorly understood. Here, we show that selective autophagy of multiple regulatory components coordinates the homeostatic state of senescence. We combined a proteomic analysis of autophagy components with protein stability profiling, identifying autophagy substrate proteins involved in several senescence-related processes. Selective autophagy of KEAP1 promoted redox homeostasis during senescence. Furthermore, selective autophagy limited translational machinery components to ameliorate senescence-associated proteotoxic stress. Lastly, selective autophagy of TNIP1 enhanced senescence-associated inflammation. These selective autophagy networks appear to operate in vivo senescence during human osteoarthritis. Our data highlight a caretaker role of autophagy in the stress support network of senescence through regulated protein stability and unravel the intertwined relationship between two important age-related processes.
    Keywords:  aging; autophagy; cellular senescence; inflammation; oxidative stress; proteostasis; regulated protein stability; selective autophagy; stress response
  22. Nat Protoc. 2021 Apr 28.
      The development of genetic tools allowed for the validation of the pro-aging and pro-disease functions of senescent cells in vivo. These discoveries prompted the development of senotherapies-pharmaceutical interventions aimed at interfering with the detrimental effect of senescent cells-that are now entering the clinical stage. However, unequivocal identification and examination of cellular senescence remains highly difficult because of the lack of universal and specific markers. Here, to overcome the limitation of measuring individual markers, we describe a detailed two-phase algorithmic assessment to quantify various senescence-associated parameters in the same specimen. In the first phase, we combine the measurement of lysosomal and proliferative features with the expression of general senescence-associated genes to validate the presence of senescent cells. In the second phase we measure the levels of pro-inflammatory markers for specification of the type of senescence. The protocol can help graduate-level basic scientists to improve the characterization of senescence-associated phenotypes and the identification of specific senescent subtypes. Moreover, it can serve as an important tool for the clinical validation of the role of senescent cells and the effectiveness of anti-senescence therapies.
  23. Cancers (Basel). 2021 Apr 15. pii: 1914. [Epub ahead of print]13(8):
      Mitochondria are well known to participate in multiple aspects of tumor formation and progression. They indeed can alter the susceptibility of cells to engage regulated cell death, regulate pro-survival signal transduction pathways and confer metabolic plasticity that adapts to specific tumor cell demands. Interestingly, a relatively poorly explored aspect of mitochondria in neoplastic disease is their contribution to the characteristic genomic instability that underlies the evolution of the disease. In this review, we summarize the known mechanisms by which mitochondrial alterations in cancer tolerate and support the accumulation of DNA mutations which leads to genomic instability. We describe recent studies elucidating mitochondrial responses to DNA damage as well as the direct contribution of mitochondria to favor the accumulation of DNA alterations.
    Keywords:  ROS; apoptosis; calcium; genomic instability; mitochondria; mitophagy; p53; tumor progression
  24. EMBO J. 2021 May 01. e106214
      BNIP3 is a mitophagy receptor with context-dependent roles in cancer, but whether and how it modulates melanoma growth in vivo remains unknown. Here, we found that elevated BNIP3 levels correlated with poorer melanoma patient's survival and depletion of BNIP3 in B16-F10 melanoma cells compromised tumor growth in vivo. BNIP3 depletion halted mitophagy and enforced a PHD2-mediated downregulation of HIF-1α and its glycolytic program both in vitro and in vivo. Mechanistically, we found that BNIP3-deprived melanoma cells displayed increased intracellular iron levels caused by heightened NCOA4-mediated ferritinophagy, which fostered PHD2-mediated HIF-1α destabilization. These effects were not phenocopied by ATG5 or NIX silencing. Restoring HIF-1α levels in BNIP3-depleted melanoma cells rescued their metabolic phenotype and tumor growth in vivo, but did not affect NCOA4 turnover, underscoring that these BNIP3 effects are not secondary to HIF-1α. These results unravel an unexpected role of BNIP3 as upstream regulator of the pro-tumorigenic HIF-1α glycolytic program in melanoma cells.
    Keywords:  BNIP3; HIF-1α; ferritinophagy; melanoma; metabolism
  25. Cancer Discov. 2021 Apr 28. pii: candisc.1637.2020. [Epub ahead of print]
      Pancreatic Neuroendocrine Tumors (PanNETs) comprise two molecular subtypes, relatively benign islet tumors (IT) and invasive, metastasis-like primary (MLP) tumors. Hitherto, the origin of aggressive MLP tumors has been obscure. Herein, using multi-omics approaches, we revealed that MLP tumors arise from IT via dedifferentiation following a reverse trajectory along the developmental pathway of islet B-cells, which results in the acquisition of a progenitor-like molecular phenotype. Functionally, the microRNA-181cd cluster induces the IT-to-MLP transition by suppressing expression of the Meis2 transcription factor, leading to upregulation of a developmental transcription factor, Hmgb3. Notably, the IT-to-MLP transition constitutes a distinct step of tumorigenesis and is separable from the classical proliferation-associated hallmark, temporally preceding accelerated proliferation of cancer cells. Furthermore, PanNET patients with elevated HMGB3 expression and an MLP transcriptional signature are associated with higher-grade tumors and worse survival. Overall, our results unveil a new mechanism that modulates cancer cell plasticity to enable malignant progression.
  26. Cell Stem Cell. 2021 Apr 15. pii: S1934-5909(21)00111-9. [Epub ahead of print]
      Personalized in vitro models for dysplasia and carcinogenesis in the pancreas have been constrained by insufficient differentiation of human pluripotent stem cells (hPSCs) into the exocrine pancreatic lineage. Here, we differentiate hPSCs into pancreatic duct-like organoids (PDLOs) with morphological, transcriptional, proteomic, and functional characteristics of human pancreatic ducts, further maturing upon transplantation into mice. PDLOs are generated from hPSCs inducibly expressing oncogenic GNAS, KRAS, or KRAS with genetic covariance of lost CDKN2A and from induced hPSCs derived from a McCune-Albright patient. Each oncogene causes a specific growth, structural, and molecular phenotype in vitro. While transplanted PDLOs with oncogenic KRAS alone form heterogenous dysplastic lesions or cancer, KRAS with CDKN2A loss develop dedifferentiated pancreatic ductal adenocarcinomas. In contrast, transplanted PDLOs with mutant GNAS lead to intraductal papillary mucinous neoplasia-like structures. Conclusively, PDLOs enable in vitro and in vivo studies of pancreatic plasticity, dysplasia, and cancer formation from a genetically defined background.
    Keywords:  CDKN2A; GNAS; IPMN; KRAS; PDAC; disease modelling; ductal pancreatic organoids; human pluripotent stem cells; in vitro differentiation; xenograft
  27. Biomedicines. 2021 Apr 06. pii: 389. [Epub ahead of print]9(4):
      Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in the US, and it is expected to be the second leading cause of cancer deaths by 2030. The lack of effective early screening tests and alarming symptoms with early undetectable micro-metastasis at the time of presentation play a vital role in the high death rate from pancreatic cancer. In addition to this, the low mutation burden in pancreatic cancer, low immunological profile, dense tumorigenesis stroma, and decreased tumor sensitivity to cytotoxic drugs contribute to the low survival rates in PDAC patients. Despite breakthroughs in chemotherapeutic and immunotherapeutic drugs, pancreatic cancer remains one of the solid tumors that exhibit meager curative rates. Therefore, researchers must dedicate more effort to understanding the pathology and immunological behavior of PDAC, in addition to properly utilizing more advanced screening modalities and new therapeutic agents. In our review, we focus mainly on the latest updates from clinical guidelines and novel therapies that have been recently investigated or are under investigation for PDAC. We used PubMed as a search tool for finding original research articles addressing the latest developments in diagnosing and treating PDAC. Additionally, we also used the clinical trials published on clinicaltrialsgov as sources for our data.
    Keywords:  pancreatic cancer; pancreatic cancer novel therapy; pancreatic cancer treatment; pancreatic ductal adenocarcinoma
  28. Exp Hematol Oncol. 2021 Apr 29. 10(1): 30
      Metastasis is a complex multistep cascade of cancer cell extravasation and invasion, in which metabolism plays an important role. Recently, a metabolic adaptation mechanism of cancer metastasis has been proposed as an emerging model of the interaction between cancer cells and the host microenvironment, revealing a deep and extensive relationship between cancer metabolism and cancer metastasis. However, research on how the host microenvironment affects cancer metabolism is mostly limited to the impact of the local tumour microenvironment at the primary site. There are few studies on how differences between the primary and secondary microenvironments promote metabolic changes during cancer progression or how secondary microenvironments affect cancer cell metastasis preference. Hence, we discuss how cancer cells adapt to and colonize in the metabolic microenvironments of different metastatic sites to establish a metastatic organotropism phenotype. The mechanism is expected to accelerate the research of cancer metabolism in the secondary microenvironment, and provides theoretical support for the generation of innovative therapeutic targets for clinical metastatic diseases.
    Keywords:  Cancer metabolism; Cancer metastasis; Organotropism; “Seed and soil” hypothesis
  29. Biomedicines. 2021 Apr 09. pii: 405. [Epub ahead of print]9(4):
      Sarcopenia is common in chronic kidney disease (CKD), and it is independently associated with morbidity and mortality. Advanced glycation end products (AGE) are mainly known as aging products. In CKD, AGE accumulate due to increased production and reduced kidney excretion. The imbalance between oxidant/antioxidant capacities in CKD patients is one of the main factors leading to AGE synthesis. AGE can, in turn, promote CKD progression and CKD-related complications by increasing reactive oxygen species generation, inducing inflammation, and promoting fibrosis. All these derangements can further increase AGE and uremic toxin accumulation and promote loss of muscle mass and function. Since the link between AGE and sarcopenia in CKD is far from being fully understood, we revised hereby the data supporting the potential contribution of AGE as mediators of oxidative stress in the pathogenesis of sarcopenia. Understanding how AGE and oxidative stress impact the onset of sarcopenia in CKD may help to identify new potential markers of disease progression and/or therapeutic targets.
    Keywords:  advanced glycation end products (AGE); chronic kidney disease; oxidative stress; sarcopenia
  30. Cancer Cell. 2021 Apr 19. pii: S1535-6108(21)00211-7. [Epub ahead of print]
  31. Elife. 2021 Apr 29. pii: e62857. [Epub ahead of print]10
      Epithelioid hemangioendothelioma (EHE) is a vascular sarcoma that metastasizes early in its clinical course and lacks an effective medical therapy. The TAZ-CAMTA1 and YAP-TFE3 fusion proteins are chimeric transcription factors and initiating oncogenic drivers of EHE. A combined proteomic/genetic screen in human cell lines identified YEATS2 and ZZZ3, components of the Ada2a-containing histone acetyltransferase (ATAC) complex, as key interactors of both fusion proteins despite the dissimilarity of the C terminal fusion partners CAMTA1 and TFE3. Integrative next generation sequencing approaches in human and murine cell lines showed that the fusion proteins drive a unique transcriptome by simultaneously hyperactivating a TEAD-based transcriptional program and modulating the chromatin environment via interaction with the ATAC complex. Interaction of the ATAC complex with both fusion proteins indicates that it is a key oncogenic driver and unifying enzymatic therapeutic target for this sarcoma. This study presents an approach to mechanistically dissect how chimeric transcription factors drive the formation of human cancers.
    Keywords:  cancer biology; chromosomes; gene expression; human; mouse
  32. J Clin Invest. 2021 Apr 29. pii: 143691. [Epub ahead of print]
      Hypoxia is a hallmark of solid tumors that promotes cell growth, survival, metastasis and confers resistance to chemo and radiotherapies. Hypoxic responses are largely mediated by the transcription factor hypoxia-inducible factor (HIF)-1α and HIF-2α. Our work demonstrates that HIF-2α is essential for colorectal cancer (CRC) progression. However, targeting hypoxic cells is difficult and tumors rapidly acquire resistance to recently developed inhibitors of HIF-2α. To overcome this limitation, we performed a small molecule screen to identify HIF-2α dependent vulnerabilities. Several known ferroptosis activators and dimethyl fumarate (DMF), a cell permeable mitochondrial metabolite derivative, led to selective synthetic lethality in HIF-2α expressing tumor enteroids. Our work demonstrates that HIF-2α integrates two independent forms of cell death via regulation of cellular iron and oxidation. First, activation of HIF-2α upreguated lipid and iron regulatory genes in colon cancer cells and colon tumors in mice and led to a ferroptosis-susceptible cell state. Secondly, via an iron dependent, lipid peroxidation-independent pathway, HIF-2α activation potentiated ROS, via irreversible cysteine oxidation and enhanced cell death. Inhibition or knockdown of HIF-2α decreased ROS and resistance to oxidative cell death in vitro and in vivo. Our results demonstrate a mechanistic vulnerability in cancer cells that were the dependent on HIF-2α that can be leveraged for colon cancer treatment.
    Keywords:  Cancer; Cell stress; Hypoxia; Metabolism; Oncology
  33. Mol Cell. 2021 Apr 16. pii: S1097-2765(21)00215-X. [Epub ahead of print]
      Autophagy is a fundamental catabolic process that uses a unique post-translational modification, the conjugation of ATG8 protein to phosphatidylethanolamine (PE). ATG8 lipidation also occurs during non-canonical autophagy, a parallel pathway involving conjugation of ATG8 to single membranes (CASM) at endolysosomal compartments, with key functions in immunity, vision, and neurobiology. It is widely assumed that CASM involves the same conjugation of ATG8 to PE, but this has not been formally tested. Here, we discover that all ATG8s can also undergo alternative lipidation to phosphatidylserine (PS) during CASM, induced pharmacologically, by LC3-associated phagocytosis or influenza A virus infection, in mammalian cells. Importantly, ATG8-PS and ATG8-PE adducts are differentially delipidated by the ATG4 family and bear different cellular dynamics, indicating significant molecular distinctions. These results provide important insights into autophagy signaling, revealing an alternative form of the hallmark ATG8 lipidation event. Furthermore, ATG8-PS provides a specific "molecular signature" for the non-canonical autophagy pathway.
    Keywords:  ATG4; ATG8; LC3-associated phagocytosis; non-canonical autophagy; phosphatidylserine
  34. Elife. 2021 Apr 27. pii: e65108. [Epub ahead of print]10
      Adiponectin is essential for the regulation of tissue substrate utilization and systemic insulin sensitivity. Clinical studies have suggested a positive association of circulating adiponectin with healthspan and lifespan. However, the direct effects of adiponectin on promoting healthspan and lifespan remain unexplored. Here, we are using an adiponectin null mouse and a transgenic adiponectin overexpression model. We directly assessed the effects of circulating adiponectin on the aging process and found that adiponectin null mice display exacerbated age-related glucose and lipid metabolism disorders. Moreover, adiponectin null mice have a significantly shortened lifespan on both chow and high-fat diet (HFD). In contrast, a transgenic mouse model with elevated circulating adiponectin levels has a dramatically improved systemic insulin sensitivity, reduced age-related tissue inflammation and fibrosis, and a prolonged healthspan and median lifespan. These results support a role of adiponectin as an essential regulator for healthspan and lifespan.
    Keywords:  cell biology; mouse
  35. Ann Surg. 2021 Mar 04.
      OBJECTIVE: To develop and validate a pretreatment prognostic score in pancreatic cancer (PDAC).BACKGROUND: Pretreatment prognostication in PDAC is important for treatment decisions but remains challenging. Available prognostic tools are derived from selected cohorts of patients who underwent resection, excluding up to 20% of patients with exploration only, and do not adequately reflect the pretreatment scenario.
    METHODS: Patients undergoing surgery for PDAC in Heidelberg from 07/2006 to 06/2014 were identified from a prospective database. Pretreatment parameters were extracted from the database and the laboratory information system. Parameters independently associated with overall survival by uni- and multivariable analyses were used to build a prognostic score. A contemporary cohort from Verona was used for external validation.
    RESULTS: In 1197 patients, multiple pretreatment parameters were associated with overall survival by univariable analyses. ASA-classification, CA19-9, CEA, CRP, albumin, and platelet count were independently associated with survival and were used to create the Heidelberg Prognostic Pancreatic Cancer (HELPP)-score. The HELPP-score was closely associated with overall survival (median survival between 31.3 and 4.8 months; 5-year survival rates between 35% and 0%) and was able to stratify survival in subgroups with or without resection as well as in CA19-9 non-secretors. In the resected subgroup the HELPP-score stratified survival independently of pathological prognostic factors. The HELPP-score was externally validated and was superior to CA19-9 in both the development and validation cohorts.
    CONCLUSION: The HELPP-score is a readily available prognostic tool based on pretreatment routine parameters to stratify survival in PDAC independently of resection status and pathological tumor stage.
  36. Antioxidants (Basel). 2021 Apr 23. pii: 657. [Epub ahead of print]10(5):
      Pancreatitis is pathologic inflammation of the pancreas characterized by acinar cell destruction and oxidative stress. Repeated pancreatic insults can result in the development of chronic pancreatitis, characterized by irreversible fibrosis of the pancreas and many secondary sequelae, ultimately leading to the loss of this important organ. We review acute pancreatitis, chronic pancreatitis, and pancreatitis-related complications. We take a close look at the pathophysiology with a focus on oxidative stress and how it contributes to the complications of the disease. We also take a deep dive into the evolution and current status of advanced therapies for management including dietary modification, antioxidant supplementation, and nuclear factor erythroid-2-related factor 2-Kelch-like ECH-associated protein 1(Nrf2-keap1) pathway activation. In addition, we discuss the surgeries aimed at managing pain and preventing further endocrine dysfunction, such as total pancreatectomy with islet auto-transplantation.
    Keywords:  Nrf2; acute pancreatitis; antioxidants; chronic pancreatitis; islet auto transplantation; oxidative stress
  37. Nat Rev Immunol. 2021 Apr 29.
      Several non-redundant features of the tumour microenvironment facilitate immunosuppression and limit anticancer immune responses. These include physical barriers to immune infiltration, the recruitment of suppressive immune cells and the upregulation of ligands on tumour cells that bind to inhibitory receptors on immune cells. Recent insights into the importance of the metabolic restrictions imposed by the tumour microenvironment on antitumour T cells have begun to inform immunotherapeutic anticancer strategies. Therapeutics that target metabolic restrictions, such as low glucose levels, a low pH, hypoxia and the generation of suppressive metabolites, have shown promise as combination therapies for different types of cancer. In this Review, we discuss the metabolic aspects of the antitumour T cell response in the context of immune checkpoint blockade, adoptive cell therapy and treatment with oncolytic viruses, and discuss emerging combination strategies.
  38. Gastroenterology. 2021 Apr 26. pii: S0016-5085(21)00682-X. [Epub ahead of print]
      BACKGROUND AND AIMS: Pancreatic ductal adenocarcinoma (PDAC) is characterised by advanced disease stage at presentation, aggressive disease biology and resistance to therapy resulting in extremely poor five-year survival <10%. PDAC is classified into transcriptional subtypes with distinct survival characteristics, although how these arise is not known. Epigenetic deregulation, rather than genetics, has been proposed to underpin progression but exactly why is unclear and hindered by technical limitations of analysing clinical samples.METHODS: Genome-wide epigenetic mapping of DNA modifications 5-methylcytosine (5mc) and 5-hydroxymethylcytosine (5hmc) using oxidative bisulphite sequencing (oxBS) from formalin embedded sections. Bioinformatics using iCluster and mutational profiling to identify overlap with transcriptional signatures in FFPE from resected patients and confirmation in vivo.
    RESULTS: We find that aggressive squamous-like PDAC subtypes result from epigenetic inactivation of loci including GATA6 that promote differentiated classical-pancreatic subtypes. We show that squamous-like PDAC transcriptional subtypes are associated with greater loss of 5hmc due to reduced expression of the 5mc-hydroxylase TET2. Furthermore, we find that SMAD4 directly supports TET2 levels in classical-pancreatic tumors and loss of SMAD4 expression is associated reduced 5hmc, GATA6 and squamous-like tumors. Importantly, enhancing TET2 stability using Metformin and VitaminC/ascorbic acid (AA) restores 5hmc and GATA6 levels, reverting squamous-like tumor phenotypes and WNT-dependence in vitro and in vivo.
    CONCLUSIONS: We identify epigenetic deregulation of pancreatic differentiation as an underpinning event behind the emergence of transcriptomic subtypes in PDAC. Our data shows that restoring epigenetic control increases biomarkers of classical-pancreatic tumors which are associated with improved therapeutic responses and survival.
    Keywords:  GATA6; SMAD4; TET2; epigenetics; pancreatic cancer
  39. Autophagy. 2021 Apr 27. 1-18
      Macroautophagy/autophagy is a cellular catabolic process that results in lysosome-mediated recycling of organelles and protein aggregates, as well as the destruction of intracellular pathogens. Its role in the maintenance of the intestinal epithelium is of particular interest, as several autophagy-related genes have been associated with intestinal disease. Autophagy and its regulatory mechanisms are involved in both homeostasis and repair of the intestine, supporting intestinal barrier function in response to cellular stress through tight junction regulation and protection from cell death. Furthermore, a clear role has emerged for autophagy not only in secretory cells but also in intestinal stem cells, where it affects their metabolism, as well as their proliferative and regenerative capacity. Here, we review the physiological role of autophagy in the context of intestinal epithelial maintenance and how genetic mutations affecting autophagy contribute to the development of intestinal disease.Abbreviations: AKT1S1: AKT1 substrate 1; AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; APC: APC regulator of WNT signaling pathway; ATF6: activating transcription factor 6; ATG: autophagy related; atg16l1[ΔIEC] mice: mice with a specific deletion of Atg16l1 in intestinal epithelial cells; ATP: adenosine triphosphate; BECN1: beclin 1; bsk/Jnk: basket; CADPR: cyclic ADP ribose; CALCOCO2: calcium binding and coiled-coil domain 2; CASP3: caspase 3; CD: Crohn disease; CDH1/E-cadherin: cadherin 1; CF: cystic fibrosis; CFTR: CF transmembrane conductance regulator; CGAS: cyclic GMP-AMP synthase; CLDN2: claudin 2; CoPEC: colibactin-producing E. coli; CRC: colorectal cancer; CYP1A1: cytochrome P450 family 1 subfamily A member 1; DC: dendritic cell; DDIT3: DNA damage inducible transcript 3; DEPTOR: DEP domain containing MTOR interacting protein; DSS: dextran sulfate sodium; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; EIF2A: eukaryotic translation initiation factor 2A; EIF2AK3: eukaryotic translation initiation factor 2 alpha kinase 3; EIF2AK4/GCN2: eukaryotic translation initiation factor 2 alpha kinase 4; ER: endoplasmic reticulum; ERN1: endoplasmic reticulum to nucleus signaling 1; GABARAP: GABA type A receptor-associated protein; HMGB1: high mobility group box 1; HSPA5/GRP78: heat shock protein family A (Hsp70) member 5; IBD: inflammatory bowel disease; IEC: intestinal epithelial cell; IFN: interferon; IFNG/IFNγ:interferon gamma; IL: interleukin; IRGM: immunity related GTPase M; ISC: intestinal stem cell; LGR5: leucine rich repeat containing G protein-coupled receptor 5; LRRK2: leucine rich repeat kinase 2; MAP1LC3A/LC3: microtubule associated protein 1 light chain 3 alpha; MAPK/JNK: mitogen-activated protein kinase; MAPK14/p38 MAPK: mitogen-activated protein kinase 14; MAPKAP1: MAPK associated protein 1; MAVS: mitochondrial antiviral signaling protein; miRNA: microRNA; MLKL: mixed lineage kinase domain like pseudokinase; MLST8: MTOR associated protein, LST8 homolog; MNV: murine norovirus; MTOR: mechanistic target of rapamycin kinase; NBR1: NBR1 autophagy cargo receptor; NLRP: NLR family pyrin domain containing; NOD: nucleotide binding oligomerization domain containing; NRBF2: nuclear receptor binding factor 2; OPTN: optineurin; OXPHOS: oxidative phosphorylation; P: phosphorylation; Patj: PATJ crumbs cell polarity complex component; PE: phosphatidyl-ethanolamine; PI3K: phosphoinositide 3-kinase; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PPARG: peroxisome proliferator activated receptor gamma; PRR5: proline rich 5; PRR5L: proline rich 5 like; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol 3-phosphate; RB1CC1/FIP200: RB1 inducible coiled-coil 1; RER: rough endoplasmic reticulum; RHEB: Ras homolog, MTORC1 binding; RICTOR: RPTOR independent companion of MTOR complex 2; RIPK1: receptor interacting serine/threonine kinase 1; ROS: reactive oxygen species; RPTOR: regulatory associated protein of MTOR complex 1; RPS6KB1: ribosomal protein S6 kinase B1; SH3GLB1: SH3 domain containing GRB2 like, endophilin B1; SNP: single-nucleotide polymorphism; SQSTM1: sequestosome 1; STAT3: signal transducer and activator of transcription 3; STING1: stimulator of interferon response cGAMP interactor 1; TA: transit-amplifying; TFEB: transcription factor EB; TFE3: transcription factor binding to IGHM enhancer 3; TGM2: transglutaminase 2; TJ: tight junction; TJP1/ZO1: tight junction protein 1; TNBS: 2,4,6-trinitrobenzene sulfonic acid; TNF/TNFα: tumor necrosis factor; Tor: target of rapamycin; TRAF: TNF receptor associated factor; TRIM11: tripartite motif containing 11; TRP53: transformation related protein 53; TSC: TSC complex subunit; Ub: ubiquitin; UC: ulcerative colitis; ULK1: unc-51 like autophagy activating kinase 1; USO1/p115: USO1 vesicle transport factor; UVRAG: UV radiation resistance associated; WIPI: WD repeat domain, phosphoinositide interacting; WNT: WNT family member; XBP1: X-box binding protein 1; ZFYVE1/DFCP1: zinc finger FYVE-type containing 1.
    Keywords:  Autophagy; Crohn disease; IBD; MTOR; intestinal epithelium; intestinal stem cells
  40. Cancers (Basel). 2021 Apr 22. pii: 2020. [Epub ahead of print]13(9):
      Cells must eliminate excess or damaged proteins to maintain protein homeostasis. To ensure protein homeostasis in the cytoplasm, cells rely on the ubiquitin-proteasome system and autophagy. In the mitochondria, protein homeostasis is regulated by mitochondria proteases, including four core ATP-dependent proteases, m-AAA, i-AAA, LonP, and ClpXP, located in the mitochondrial membrane and matrix. This review will discuss the function of mitochondrial proteases, with a focus on ClpXP as a novel therapeutic target for the treatment of malignancy. ClpXP maintains the integrity of the mitochondrial respiratory chain and regulates metabolism by degrading damaged and misfolded mitochondrial proteins. Inhibiting ClpXP genetically or chemically impairs oxidative phosphorylation and is toxic to malignant cells with high ClpXP expression. Likewise, hyperactivating the protease leads to increased degradation of ClpXP substrates and kills cancer cells. Thus, targeting ClpXP through inhibition or hyperactivation may be novel approaches for patients with malignancy.
    Keywords:  AML; ClpXP; cancer; mitochondria; protease
  41. Elife. 2021 Apr 30. pii: e62915. [Epub ahead of print]10
      High dimensional cytometry is an innovative tool for immune monitoring in health and disease, it has provided novel insight into the underlying biology as well as biomarkers for a variety of diseases. However, the analysis of large multiparametric datasets usually requires specialist computational knowledge. Here we describe ImmunoCluster ( an R package for immune profiling cellular heterogeneity in high dimensional liquid and imaging mass cytometry, and flow cytometry data, designed to facilitate computational analysis by a non-specialist. The analysis framework implemented within ImmunoCluster is readily scalable to millions of cells and provides a variety of visualization and analytical approaches, as well as a rich array of plotting tools that can be tailored to users' needs. The protocol consists of three core computational stages: 1, data import and quality control; 2, dimensionality reduction and unsupervised clustering; and 3, annotation and differential testing, all contained within an R-based open-source framework.
    Keywords:  computational biology; human; immunology; inflammation; systems biology
  42. Bioinformatics. 2021 Apr 26. pii: btab244. [Epub ahead of print]
      SUMMARY: The heterogeneous cell types of the tumor-immune microenvironment (TIME) play key roles in determining cancer progression, metastasis, and response to treatment. We report the development of TIMEx, a novel tumor-immune microenvironment deconvolution method emphasizing on estimating infiltrating immune cells for bulk transcriptomics using pan-cancer single-cell RNA-seq signatures. We also implemented a comprehensive, user-friendly web-portal for users to evaluate TIMEx and other deconvolution methods with bulk transcriptomic profiles.AVAILABILITY: TIMEx web portal is freely accessible at
    SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
  43. STAR Protoc. 2021 Jun 18. 2(2): 100448
      Chronic stress has adverse consequences on many organ systems and physiological processes. However, existing protocols show large variability in response and are not suitable for female mice. Here, we provide a step-by-step protocol for establishing a reliable chronic stress model in mice that can be used in a variety of physiological settings. This protocol has been tested to be effective to produce a consistent response to stress in several mouse strains (C57BL/6J, 129X1/SvJ, B6.V-Lepob/J) and both sexes. For complete details on the use and execution of this protocol, please refer to Ip et al. (2019).
    Keywords:  Metabolism; Model Organisms; Neuroscience
  44. Cancers (Basel). 2021 Apr 20. pii: 1973. [Epub ahead of print]13(8):
      Tumor cells display important plasticity potential, which contributes to intratumoral heterogeneity. Notably, tumor cells have the ability to retrodifferentiate toward immature states under the influence of their microenvironment. Importantly, this phenotypical conversion is paralleled by a metabolic rewiring, and according to the metabostemness theory, metabolic reprogramming represents the first step of epithelial-to-mesenchymal transition (EMT) and acquisition of stemness features. Most cancer stem cells (CSC) adopt a glycolytic phenotype even though cells retain functional mitochondria. Such adaptation is suggested to reduce the production of reactive oxygen species (ROS), protecting CSC from detrimental effects of ROS. CSC may also rely on glutaminolysis or fatty acid metabolism to sustain their energy needs. Besides pro-inflammatory cytokines that are well-known to initiate the retrodifferentiation process, the release of catecholamines in the microenvironment of the tumor can modulate both EMT and metabolic changes in cancer cells through the activation of EMT transcription factors (ZEB1, Snail, or Slug (SNAI2)). Importantly, the acquisition of stem cell properties favors the resistance to standard care chemotherapies. Hence, a better understanding of this process could pave the way for the development of therapies targeting CSC metabolism, providing new strategies to eradicate the whole tumor mass in cancers with unmet needs.
    Keywords:  cancer stem cell; catecholamines; cell plasticity; epithelial-to-mesenchymal transition; metabolism reprogramming
  45. Nature. 2021 Apr 28.
      Somatic mutations drive the development of cancer and may contribute to ageing and other diseases1,2. Despite their importance, the difficulty of detecting mutations that are only present in single cells or small clones has limited our knowledge of somatic mutagenesis to a minority of tissues. Here, to overcome these limitations, we developed nanorate sequencing (NanoSeq), a duplex sequencing protocol with error rates of less than five errors per billion base pairs in single DNA molecules from cell populations. This rate is two orders of magnitude lower than typical somatic mutation loads, enabling the study of somatic mutations in any tissue independently of clonality. We used this single-molecule sensitivity to study somatic mutations in non-dividing cells across several tissues, comparing stem cells to differentiated cells and studying mutagenesis in the absence of cell division. Differentiated cells in blood and colon displayed remarkably similar mutation loads and signatures to their corresponding stem cells, despite mature blood cells having undergone considerably more divisions. We then characterized the mutational landscape of post-mitotic neurons and polyclonal smooth muscle, confirming that neurons accumulate somatic mutations at a constant rate throughout life without cell division, with similar rates to mitotically active tissues. Together, our results suggest that mutational processes that are independent of cell division are important contributors to somatic mutagenesis. We anticipate that the ability to reliably detect mutations in single DNA molecules could transform our understanding of somatic mutagenesis and enable non-invasive studies on large-scale cohorts.
  46. Biomedicines. 2021 Apr 02. pii: 373. [Epub ahead of print]9(4):
      Genetic alterations, especially the K-Ras mutation, carry the heaviest burden in the progression of pancreatic precursor lesions into pancreatic ductal adenocarcinoma (PDAC). The tumor microenvironment is one of the challenges that hinder the therapeutic approaches from functioning sufficiently and leads to the immune evasion of pancreatic malignant cells. Mastering the mechanisms of these two hallmarks of PDAC can help us in dealing with the obstacles in the way of treatment. In this review, we have analyzed the signaling pathways involved in PDAC development and the immune system's role in pancreatic cancer and immune checkpoint inhibition as next-generation therapeutic strategy. The direct targeting of the involved signaling molecules and the immune checkpoint molecules, along with a combination with conventional therapies, have reached the most promising results in pancreatic cancer treatment.
    Keywords:  PDAC; gene mutation; immune checkpoint; pancreatic adenocarcinoma; pancreatic cancer; signaling pathway
  47. Cancers (Basel). 2021 Apr 03. pii: 1698. [Epub ahead of print]13(7):
      In rodents, we identified a physiologic process within the normal liver that creates a pre-metastatic niche. This physiology is weaning-induced liver involution, characterized by hepatocyte cell death, immune influx, and extracellular matrix remodeling. Here, using weaning-induced liver involution as a model of a physiologically regulated pro-metastatic niche, we investigate how liver involution supports breast cancer metastasis. Liver metastases were induced in BALB/c immune competent hosts by portal vein injection of D2OR (low metastatic) or D2A1 (high metastatic) mouse mammary tumor cells. Tumor incidence and multiplicity increased in involution hosts with no evidence of a proliferation advantage. D2OR tumor cell extravasation, seeding, and early survival were not enhanced in the involuting group compared to the nulliparous group. Rather, the involution metastatic advantage was observed at 14 days post tumor cell injection. This metastatic advantage associated with induction of immune tolerance in the involution host liver, reproductive state dependent intra-tumoral immune composition, and CD8-dependent suppression of metastases in nulliparous hosts. Our findings suggest that the normal postpartum liver is in an immune suppressed state, which can provide a pro-metastatic advantage to circulating breast cancer cells. Potential relevance to women is suggested as a postpartum diagnosis of breast cancer is an independent predictor of liver metastasis.
    Keywords:  breast cancer; liver involution; liver metastasis; metastatic niche
  48. Cancers (Basel). 2021 Apr 08. pii: 1776. [Epub ahead of print]13(8):
      Pancreatic cancer has one of the worst prognoses of any human malignancy and leukocyte infiltration is a major prognostic marker of the disease. As current immunotherapies confer negligible survival benefits, there is a need to better characterise leukocytes in pancreatic cancer to identify better therapeutic strategies. In this study, we analysed 32 human pancreatic cancer patients from two independent cohorts. A multi-parameter mass-cytometry analysis was performed on 32,000 T-cells from eight patients. Single-cell RNA sequencing dataset analysis was performed on a cohort of 24 patients. Multiplex immunohistochemistry imaging and spatial analysis were performed to map immune infiltration into the tumour microenvironment. Regulatory T-cell populations demonstrated highly immunosuppressive states with high TIGIT, ICOS and CD39 expression. CD8+ T-cells were found to be either in senescence or an exhausted state. The exhausted CD8 T-cells had low PD-1 expression but high TIGIT and CD39 expression. These findings were corroborated in an independent pancreatic cancer single-cell RNA dataset. These data suggest that T-cells are major players in the suppressive microenvironment of pancreatic cancer. Our work identifies multiple novel therapeutic targets that should form the basis for rational design of a new generation of clinical trials in pancreatic ductal adenocarcinoma.
    Keywords:  CD39; ICOS; TIGIT; immune checkpoints; pancreatic cancer; regulatory T-cells; senescent T-cells
  49. Cells. 2021 Apr 21. pii: 966. [Epub ahead of print]10(5):
      Pancreatic ductal adenocarcinoma (PDAC) displays a particularly poor prognosis and low survival rate, mainly due to late diagnosis and high incidence of chemotherapy resistance. Genomic aberrations, together with changes in the epigenomic profile, elicit a shift in cellular signaling response and a transcriptional reprograming in pancreatic tumors. This endows them with malignant attributes that enable them to not only overcome chemotherapeutic challenges, but to also attain diverse oncogenic properties. In fact, certain genetic amplifications elicit a rewiring of calcium signaling, which can confer ER stress resistance to tumors while also aberrantly activating known drivers of oncogenic programs such as NFAT. While calcium is a well-known second messenger, the transcriptional programs driven by aberrant calcium signaling remain largely undescribed in pancreatic cancer. In this review, we focus on calcium-dependent signaling and its role in epigenetic programs and transcriptional regulation. We also briefly discuss genetic aberration events, exemplifying how genetic alterations can rewire cellular signaling cascades, including calcium-dependent ones.
    Keywords:  ER stress; NFAT; PDAC; SOCE; calcium; epigenetics; transcription
  50. Cancers (Basel). 2021 Apr 01. pii: 1669. [Epub ahead of print]13(7):
      Improving outcomes among patients with resectable pancreatic cancer is one of the greatest challenges of modern medicine. Major improvements in survival will result from the development of novel therapies. However, optimising existing pathways, so that patients realise benefits of already proven treatments, presents a clear opportunity to improve outcomes in the short term. This narrative review will focus on treatments and interventions where there is a clear evidence base to improve outcomes in pancreatic cancer, and where there is also evidence of variation and under-treatment. Avoidance of preoperative biliary drainage, treatment of pancreatic exocrine insufficiency, prehabiliation and enhanced recovery after surgery, reducing perioperative complications, optimising opportunities for elderly patients to receive therapy, optimising adjuvant chemotherapy and regular surveillance after surgery are some of the strategies discussed. Each treatment or pathway change represents an opportunity for marginal gain. Accumulation of marginal gains can result in considerable benefit to patients. Given that these interventions already have evidence base, they can be realised quickly and economically.
    Keywords:  ERAS; adjuvant chemotherapy; biliary drainage; pancreatic cancer; pancreatic exocrine insufficiency; prehabilitation
  51. Cancers (Basel). 2021 Apr 13. pii: 1843. [Epub ahead of print]13(8):
      The aim of this study was to perform a simplified radiomic analysis of pancreatic ductal adenocarcinoma based on qualitative and quantitative tumor features and to compare the results between metastatic and non-metastatic patients. A search of our radiological, surgical, and pathological databases identified 1218 patients with a newly diagnosed pancreatic ductal adenocarcinoma who were referred to our Institution between January 2014 and December 2018. Computed Tomography (CT) examinations were reviewed analyzing qualitative and quantitative features. Two hundred eighty-eight patients fulfilled the inclusion criteria and were included in this study. Overall, metastases were present at diagnosis in 86/288 patients, while no metastases were identified in 202/288 patients. Ill-defined margins and a hypodense appearance on portal-phase images were significantly more common among patients with metastases compared to non-metastatic patients (p < 0.05). Metastatic tumors showed a significantly larger size and significantly lower arterial index, perfusion index, and permeability index compared to non-metastatic tumors (p < 0.05). In the management of pancreatic ductal adenocarcinoma, early detection and correct staging are key elements. The study of computerized tomography characteristics of pancreatic ductal adenocarcinoma showed substantial differences, both qualitative and quantitative, between metastatic and non-metastatic disease.
    Keywords:  CT; metastasis; pancreatic adenocarcinoma; pancreatic cancer; radiomics
  52. Nat Immunol. 2021 Apr 26.
      Although the pathological significance of tumor-associated macrophage (TAM) heterogeneity is still poorly understood, TAM reprogramming is viewed as a promising anticancer therapy. Here we show that a distinct subset of TAMs (F4/80hiCD115hiC3aRhiCD88hi), endowed with high rates of heme catabolism by the stress-responsive enzyme heme oxygenase-1 (HO-1), plays a critical role in shaping a prometastatic tumor microenvironment favoring immunosuppression, angiogenesis and epithelial-to-mesenchymal transition. This population originates from F4/80+HO-1+ bone marrow (BM) precursors, accumulates in the blood of tumor bearers and preferentially localizes at the invasive margin through a mechanism dependent on the activation of Nrf2 and coordinated by the NF-κB1-CSF1R-C3aR axis. Inhibition of F4/80+HO-1+ TAM recruitment or myeloid-specific deletion of HO-1 blocks metastasis formation and improves anticancer immunotherapy. Relative expression of HO-1 in peripheral monocyte subsets, as well as in tumor lesions, discriminates survival among metastatic melanoma patients. Overall, these results identify a distinct cancer-induced HO-1+ myeloid subgroup as a new antimetastatic target and prognostic blood marker.
  53. Semin Cancer Biol. 2021 Apr 24. pii: S1044-579X(21)00113-9. [Epub ahead of print]
      The acquisition of DNA damage is an early driving event in tumorigenesis. Premalignant lesions show activated DNA damage responses and inactivation of DNA damage checkpoints promotes malignant transformation. However, DNA damage is also a targetable vulnerability in cancer cells. This requires a detailed understanding of the cellular and molecular mechanisms governing DNA integrity. Here, we review current work on DNA damage in tumorigenesis. We discuss DNA double strand break repair, how repair pathways contribute to tumorigenesis, and how double strand breaks are linked to the tumor microenvironment. Next, we discuss the role of oncogenes in promoting DNA damage through replication stress. Finally, we discuss our current understanding on DNA damage in micronuclei and discuss therapies targeting these DNA damage pathways.
    Keywords:  DNA damage; Genome instability; Tumorigenesis
  54. Trends Cancer. 2021 Apr 23. pii: S2405-8033(21)00066-2. [Epub ahead of print]
      Although targeting programmed death 1/programmed death ligand 1 (PD-1/PD-L1) has achieved durable responses and disease remission in patients with certain cancers, relatively low response rates and emerging resistance limit its clinical application. Hence, a more thorough understanding of regulatory mechanisms of the PD-1/PD-L1 axis is vital for developing combined therapeutic strategies to overcome hurdles of PD-1/PD-L1 blockade. Increasing evidence has demonstrated that PD-L1 can be secreted into the extracellular space or translocated into the nucleus, which also plays a critical role in regulating cancer immune evasion, tumorigenesis, and immunotherapy. In this review, we summarize these emerging roles of extracellular and nuclear PD-L1 and discuss future research directions and potential opportunities in translational medicine.
    Keywords:  cancer immunotherapy; exosomes; extracellular PD-L1; immune checkpoint; nuclear PD-L1; pyroptosis
  55. FASEB J. 2021 May;35(5): e21597
      Aging is a gradual biological process characterized by a decrease in cellular and organism functions. Aging-related processes involve changes in the expression and activity of several proteins. Here, we identified the transmembrane protease serine 11a (TMPRSS11a) as a new age-specific protein that plays an important role in skin wound healing. TMPRSS11a levels increased with age in rodent and human skin and gingival samples. Strikingly, overexpression of TMPRSS11a decreased cell migration and spreading, and inducing cellular senescence. Mass spectrometry, bioinformatics, and functional analyses revealed that TMPRSS11a interacts with integrin β1 through an RGD sequence contained within the C-terminal domain and that this motif was relevant for cell migration. Moreover, TMPRSS11a was associated with cellular senescence, as shown by overexpression and downregulation experiments. In agreement with tissue-specific expression of TMPRSS11a, shRNA-mediated downregulation of this protein improved wound healing in the skin, but not in the skeletal muscle of old mice, where TMPRSS11a is undetectable. Collectively, these findings indicate that TMPRSS11a is a tissue-specific factor relevant for wound healing, which becomes elevated with aging, promoting cellular senescence and inhibiting cell migration and skin repair.
    Keywords:  RGD motif; aging; beta1 integrin; cell migration
  56. Oncogene. 2021 Apr 29.
      Ferroptosis, a form of regulated cell death triggered by lipid peroxidation, was recently identified as an important mechanism in radiotherapy (RT)-mediated tumor suppression and radioresistance, although the exact genetic contexts in which to target ferroptosis in RT remains to be defined. p53 is the most commonly mutated gene in human cancers and a major effector to RT. Here, we identify ferroptosis as a critical mechanism to mediate p53 function in tumor radiosensitivity. Mechanistically, RT-mediated p53 activation antagonizes RT-induced SLC7A11 expression and represses glutathione synthesis, thereby promoting RT-induced lipid peroxidation and ferroptosis. p53 deficiency promotes radioresistance in cancer cells or tumors at least partly through SLC7A11-mediated ferroptosis inhibition. Ferroptosis inducers (FINs) that inhibit SLC7A11 exert significant radiosensitizing effects in tumor organoids and patient-derived xenografts with p53 mutation or deficiency. Finally, we show that RT-induced ferroptosis correlates with p53 activation and better clinical outcomes to RT in cancer patients. Together, our study uncovers a previously unappreciated role of ferroptosis in p53-mediated radiosensitization and suggest using FINs in combination with RT to treat p53-mutant cancers.
  57. J Cell Sci. 2021 Apr 15. pii: jcs254409. [Epub ahead of print]134(8):
      Cytokinesis is the process that separates a cell into two daughter cells at the end of mitosis. Most of our knowledge of cytokinesis comes from overexpression studies, which affects our interpretation of protein function. Gene editing can circumvent this issue by introducing functional mutations or fluorescent probes directly into a gene locus. However, despite its potential, gene editing is just starting to be used in the field of cytokinesis. Here, we discuss the benefits of using gene editing tools for the study of cytokinesis and highlight recent studies that successfully used CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) technology to answer critical questions regarding the function of cytokinesis proteins. We also present methodologies for editing essential genes and discuss how CRISPR interference (CRISPRi) and activation (CRISPRa) can enable precise control of gene expression to answer important questions in the field. Finally, we address the need for gene editing to study cytokinesis in more physiologically relevant contexts. Therefore, this Review provides a roadmap for gene editing to be used in the study of cytokinesis and other cellular processes.
    Keywords:  Actomyosin; CRISPR; Cytokinesis; Gene editing; RhoA
  58. Oncogene. 2021 Apr 29.
      Mitochondrial oxidative phosphorylation (OXPHOS) is a vital regulator of tumor metastasis. However, the mechanisms governing OXPHOS to facilitate tumor metastasis remain unclear. In this study, we discovered that arginine 21(R21) and lysine 108 (K108) of mitochondrial ribosomal protein S23 (MRPS23) was methylated by the protein arginine methyltransferase 7 (PRMT7) and SET-domain-containing protein 6 (SETD6), respectively. R21 methylation accelerated the poly-ubiquitin-dependent degradation of MRPS23 to a low level. The MRPS23 degradation inhibited OXPHOS with elevated mtROS level, which consequently increased breast cancer cell invasion and metastasis. In contrast, K108 methylation increased MRPS23 stability, and K108 methylation coordinated with R21 methylation to maintain a low level of MRPS23, which was in favor of supporting breast cancer cell survival through regulating OXPHOS. Consistently, R21 and K108 methylation was correlated with malignant breast carcinoma. Significantly, our findings unveil a unique mechanism of controlling OXPHOS by arginine and lysine methylation and point to the impact of the PRMT7-SETD6-MRPS23 axis during breast cancer metastasis.
  59. Int J Mol Sci. 2021 Apr 02. pii: 3698. [Epub ahead of print]22(7):
      The past decade revealed that cell identity changes, such as dedifferentiation or transdifferentiation, accompany the insulin-producing β-cell decay in most diabetes conditions. Mapping and controlling the mechanisms governing these processes is, thus, extremely valuable for managing the disease progression. Extracellular glucose is known to influence cell identity by impacting the redox balance. Here, we use global proteomics and pathway analysis to map the response of differentiating human pancreatic progenitors to chronically increased in vitro glucose levels. We show that exogenous high glucose levels impact different protein subsets in a concentration-dependent manner. In contrast, regardless of concentration, glucose elicits an antipodal effect on the proteome landscape, inducing both beneficial and detrimental changes in regard to achieving the desired islet cell fingerprint. Furthermore, we identified that only a subgroup of these effects and pathways are regulated by changes in redox balance. Our study highlights a complex effect of exogenous glucose on differentiating pancreas progenitors characterized by a distinct proteome signature.
    Keywords:  cell fate; cell identity; exogenous glucose; hiPSC; in vitro differentiation; pancreatic endocrine progenitors; proteomics; signaling pathway analyses
  60. Inflammation. 2021 Apr 27.
      Treatment of cancer cachexia remains an unmet need. The host-tumour interface and the resulting sequestration of the pro-inflammatory cytokine Il-1β is critical in cachexia development. Neuroinflammation mediated via IL-1β through the hypothalamic pituitary axis results in increased muscle proteolysis and adipose lipolysis, thus creating a prolonged stress-like environment with loss of appetite and increased resting energy expenditure. Recent trials using a monoclonal antibody targeting IL-1β, canakinumab, have shown a potential role in lung cancer; however, a potential role of targeting IL-1β to treat cachexia in patients with lung cancer is unclear, yet the underlying pathophysiology provides a sound rationale that this may be a viable therapeutic approach.
    Keywords:  Cachexia; Inflammation; Interleukin-1 beta
  61. J Cell Physiol. 2021 Apr 26.
      Pancreatic regeneration after acute pancreatitis is critical in the normal restoration of pancreatic exocrine function, the inhibition of which can cause severe complications including pancreatic exocrine insufficiency. However, the regulators of pancreatic regeneration and the underlying mechanisms remain uncovered. Here, using the inducible Tet-on system, we found that regenerating family member 4 (Reg4) knockdown significantly impaired pancreatic regeneration after pancreatitis. Both acinar-to-ductal metaplasia and the resolution of pancreatitis during regeneration were affected by Reg4 knockdown. Further investigations confirmed that Reg4 exerted its function through regulating Notch activation both in vitro and in vivo. Our study revealed Reg4 as a new regulator and potential therapeutic target for pancreatic regeneration.
    Keywords:  ADM; Notch; Reg4; cell proliferation; pancreatic regeneration
  62. Cell Metab. 2021 Apr 22. pii: S1550-4131(21)00169-8. [Epub ahead of print]
      NAD(H) and NADP(H) have traditionally been viewed as co-factors (or co-enzymes) involved in a myriad of oxidation-reduction reactions including the electron transport in the mitochondria. However, NAD pathway metabolites have many other important functions, including roles in signaling pathways, post-translational modifications, epigenetic changes, and regulation of RNA stability and function via NAD-capping of RNA. Non-oxidative reactions ultimately lead to the net catabolism of these nucleotides, indicating that NAD metabolism is an extremely dynamic process. In fact, recent studies have clearly demonstrated that NAD has a half-life in the order of minutes in some tissues. Several evolving concepts on the metabolism, transport, and roles of these NAD pathway metabolites in disease states such as cancer, neurodegeneration, and aging have emerged in just the last few years. In this perspective, we discuss key recent discoveries and changing concepts in NAD metabolism and biology that are reshaping the field. In addition, we will pose some open questions in NAD biology, including why NAD metabolism is so fast and dynamic in some tissues, how NAD and its precursors are transported to cells and organelles, and how NAD metabolism is integrated with inflammation and senescence. Resolving these questions will lead to significant advancements in the field.
    Keywords:  NAD pathway metabolites; NAD(+); aging; disease; humans; mitochondria; transport; vitamin B3
  63. Gut. 2021 Apr 27. pii: gutjnl-2019-319807. [Epub ahead of print]
    Keywords:  immune response; intestinal microbiology; pancreatic cancer