bims-stacyt Biomed News
on Paracrine crosstalk between cancer and the organism
Issue of 2019‒09‒29
seven papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Front Immunol. 2019 ;10 2056
    Hanlon MM, Rakovich T, Cunningham CC, Ansboro S, Veale DJ, Fearon U, McGarry T.
      Objectives: Oncostatin M (OSM), a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family, has been implicated in the pathogenesis of autoimmune diseases. Here we investigate the mechanisms by which its synergistic interactions with TNFα regulate the cellular bioenergetics and invasive function of synovial cells from patients with Rheumatoid Arthritis. Methods: Primary RA synovial fibroblasts (RAFLS) and human umbilical vein endothelial cells (HUVEC) were cultured with OSM alone or in combination with TNFα. Pro-inflammatory cytokines, angiogenic growth factors and adhesion molecules were quantified by real-time PCR and ELISA. Invasion, angiogenesis and cellular adhesion were quantified by Transwell invasion chambers, Matrigel tube formation assays, and adhesion binding assays. Cellular bioenergetics was assessed using the Seahorse XFe96 Analyser. Key metabolic genes (GLUT-1, HK2, PFKFB3, HIF1α, LDHA, PKM2) and transcription factor STAT3 were measured using real-time PCR and western blot. Results: OSM differentially regulates pro-inflammatory mediators in RAFLS and HUVEC, with IL-6, MCP-1, ICAM-1, and VEGF all significantly induced, in contrast to the observed inhibition of IL-8 and GROα, with opposing effects observed for VCAM-1 depending on cell type. Functionally, OSM significantly induced angiogenic network formation, adhesion, and invasive mechanisms. This was accompanied by a change in the cellular bioenergetic profile of the cells, where OSM significantly increased the ECAR/OCR ratio in favor of glycolysis, paralleled by induction of the glucose transporter GLUT-1 and key glycolytic enzymes (HK2, PFKFB3, HIF1α). OSM synergizes with TNFα to differentially regulate pro-inflammatory mechanisms in RAFLS and HUVEC. Interestingly, OSM differentially synergizes with TNFα to regulate metabolic reprogramming, where induction of glycolytic activity with concomitant attenuation of mitochondrial respiration and ATP activity was demonstrated in RAFLS but not in HUVEC. Finally, we identified a mechanism, whereby the combination of OSM with TNFα induces transcriptional activity of STAT3 only in RAFLS, with no effect observed in HUVEC. Conclusion: STAT3 mediates the differential effects of OSM and TNFα on RAFLS and EC function. Targeting OSM or downstream signaling pathways may lead to new potential therapeutic or adjuvant strategies, particularly for those patients who have sub-optimal responses to TNFi.
    Keywords:  JAK-STAT signaling; cellular bioenergetics; pro-inflammatory cytokines; rheumatoid arthritis; synovial fibroblasts
  2. Front Mol Biosci. 2019 ;6 85
    Fitzpatrick SF.
      Metabolic reprogramming of innate immune cells occurs during both the hyperinflammatory and immunotolerant phases of sepsis. The hypoxia inducible factor (HIF) signaling pathway plays a vital role in regulating these metabolic changes. This review initially summarizes the HIF-driven changes in metabolic dynamics of innate immune cells in response to sepsis. The hyperinflammatory phase of sepsis is accompanied by a metabolic switch from oxidative phosphorylation to HIF-1α mediated glycolysis. Furthermore, HIF driven alterations in arginine metabolism also occur during this phase. This promotes sepsis pathophysiology and the development of clinical symptoms. These early metabolic changes are followed by a late immunotolerant phase, in which suppressed HIF signaling promotes a switch from aerobic glycolysis to fatty acid oxidation, with a subsequent anti-inflammatory response developing. Recently the molecular mechanisms controlling HIF activation during these early and late phases have begun to be elucidated. In the final part of this review the contribution of toll-like receptors, transcription factors, metabolic intermediates, kinases and reactive oxygen species, in governing the HIF-induced metabolic reprogramming of innate immune cells will be discussed. Importantly, understanding these regulatory mechanisms can lead to the development of novel diagnostic and therapeutic strategies targeting the HIF-dependent metabolic state of innate immune cells.
    Keywords:  HIF; hypoxia inducible factor; innate immune cells; metabolism; molecular mechanism; sepsis
  3. Int J Mol Sci. 2019 Sep 24. pii: E4742. [Epub ahead of print]20(19):
    Kappler M, Pabst U, Weinholdt C, Taubert H, Rot S, Kaune T, Kotrba J, Porsch M, Güttler A, Bache M, Krohn K, Bull F, Riemann A, Wickenhauser C, Seliger B, Schubert J, Al-Nawas B, Thews O, Grosse I, Vordermark D, Eckert AW.
      The transcription factor hypoxia-inducible factor 1 (HIF1) is the crucial regulator of genes that are involved in metabolism under hypoxic conditions, but information regarding the transcriptional activity of HIF1 in normoxic metabolism is limited. Different tumor cells were treated under normoxic and hypoxic conditions with various drugs that affect cellular metabolism. HIF1α was silenced by siRNA in normoxic/hypoxic tumor cells, before RNA sequencing and bioinformatics analyses were performed while using the breast cancer cell line MDA-MB-231 as a model. Differentially expressed genes were further analyzed and validated by qPCR, while the activity of the metabolites was determined by enzyme assays. Under normoxic conditions, HIF1 activity was significantly increased by (i) glutamine metabolism, which was associated with the release of ammonium, and it was decreased by (ii) acetylation via acetyl CoA synthetase (ACSS2) or ATP citrate lyase (ACLY), respectively, and (iii) the presence of L-ascorbic acid, citrate, or acetyl-CoA. Interestingly, acetylsalicylic acid, ibuprofen, L-ascorbic acid, and citrate each significantly destabilized HIF1α only under normoxia. The results from the deep sequence analyses indicated that, in HIF1-siRNA silenced MDA-MB-231 cells, 231 genes under normoxia and 1384 genes under hypoxia were transcriptionally significant deregulated in a HIF1-dependent manner. Focusing on glycolysis genes, it was confirmed that HIF1 significantly regulated six normoxic and 16 hypoxic glycolysis-associated gene transcripts. However, the results from the targeted metabolome analyses revealed that HIF1 activity affected neither the consumption of glucose nor the release of ammonium or lactate; however, it significantly inhibited the release of the amino acid alanine. This study comprehensively investigated, for the first time, how normoxic HIF1 is stabilized, and it analyzed the possible function of normoxic HIF1 in the transcriptome and metabolic processes of tumor cells in a breast cancer cell model. Furthermore, these data imply that HIF1 compensates for the metabolic outcomes of glutaminolysis and, subsequently, the Warburg effect might be a direct consequence of the altered amino acid metabolism in tumor cells.
    Keywords:  HIF1α; L-ascorbic acid; Warburg effect; acetylsalicylic acid; glutamine; glutaminolysis; glycolysis; hypoxia; metabolism; normoxia; tumor
  4. Front Endocrinol (Lausanne). 2019 ;10 607
    Rharass T, Lucas S.
      Bone marrow adipocytes (BMAds) accumulate in aging, menopause, and metabolic diseases such as Type 2 diabetes. These osteoporotic conditions are associated with oxidative stress and hyperglycemia which are both considered as critical factors underlying bone fragility. Glucose excess and reactive oxygen species (ROS) are known to favor adipogenesis over osteoblastogenesis. In this study, we investigated whether high glucose exposure could determine dysfunction of mature BMAds, specifically through ROS production. The effects of low (LG, 5 mM) or high glucose (HG, 25 mM) concentrations were examined using human bone mesenchymal stromal cells (hBMSCs) in the time course of differentiation, and, up to 21 days once adipocytes were mature. HG did not alter the adipocyte differentiation process of hBMSCs. Yet, after 21 days under HG exposure, PPARG, CEBPA, and adiponectin mRNA expressions were decreased. These alterations were also observed following adipogenic inducer withdrawal as well as in adipocytes fully differentiated in LG then cultured in HG for the last 11 days. Without inducers, HG condition also led to decreased leptin mRNA level. Importantly, intracellular and extracellular ROS concentrations measured using Amplex Red were significantly raised by 50% under HG exposure. This rise was observed once adipocytes ended differentiation and was reproduced within the different cell culture settings without any cytotoxicity. Among genes involved in ROS metabolism, the mRNA level of the H2O2 generating enzyme NOX4 was found upregulated in the presence of HG. Following cell separation, mature BMAds were shown to overproduce ROS and to display the gene alterations in contrast to non-lipid-laden cells. Finally, a non-lethal treatment with a pro-oxidant agent under LG condition reduces the mRNA levels of PPARG, adiponectin, and leptin as the HG condition does in the absence of inducers, and amplifies the effect of glucose excess on gene expression. HG concentration drives mature BMAds toward altered expression of the main adipokines and transcriptional factors. These perturbations are associated with a rise in ROS generation likely mediated through enhanced expression of NOX4. Mature BMAds are thus responsive to changes in glucose and ROS concentrations, which is relevant regarding with their phenotype and function in age- or metabolic disease-related osteoporosis.
    Keywords:  adipocyte; bone marrow; glucose; hyperglycemia; mesenchymal skeletal stem cells; osteoporosis; oxidative stress; reactive oxygen species
  5. Cell Mol Immunol. 2019 Sep 24.
    Unamuno X, Gómez-Ambrosi J, Ramírez B, Rodríguez A, Becerril S, Valentí V, Moncada R, Silva C, Salvador J, Frühbeck G, Catalán V.
      The NLRP3-IL-1β pathway plays an important role in adipose tissue (AT)-induced inflammation and the development of obesity-associated comorbidities. We aimed to determine the impact of NLRP3 on obesity and its associated metabolic alterations as well as its role in adipocyte inflammation and extracellular matrix (ECM) remodeling. Samples obtained from 98 subjects were used in a case-control study. The expression of different components of the inflammasome as well as their main effectors and inflammation- and ECM remodeling-related genes were analyzed. The impact of blocking NLRP3 using siRNA in lipopolysaccharide (LPS)-mediated inflammation and ECM remodeling signaling pathways was evaluated. We demonstrated that obesity (P < 0.01), obesity-associated T2D (P < 0.01) and NAFLD (P < 0.05) increased the expression of different components of the inflammasome as well as the expression and release of IL-1β and IL-18 in AT. We also found that obese patients with T2D exhibited increased (P < 0.05) hepatic gene expression levels of NLRP3, IL1B and IL18. We showed that NLRP3, but not NLRP1, is regulated by inflammation and hypoxia in visceral adipocytes. We revealed that the inhibition of NLRP3 in human visceral adipocytes significantly blocked (P < 0.01) LPS-induced inflammation by downregulating the mRNA levels of CCL2, IL1B, IL6, IL8, S100A8, S100A9, TLR4 and TNF as well as inhibiting (P < 0.01) the secretion of IL1-β into the culture medium. Furthermore, blocking NLRP3 attenuated (P < 0.01) the LPS-induced expression of important molecules involved in AT fibrosis (COL1A1, COL4A3, COL6A3 and MMP2). These novel findings provide evidence that blocking the expression of NLRP3 reduces AT inflammation with significant fibrosis attenuation.
    Keywords:  Inflammasone; Inflammation; NLRP3; Nonalcoholic fatty liver disease; Obesity; Type 2 diabetes
  6. Cells. 2019 Sep 12. pii: E1071. [Epub ahead of print]8(9):
    Fan Y, Simmen T.
      The past decade has seen the emergence of endoplasmic reticulum (ER) chaperones as key determinants of contact formation between mitochondria and the ER on the mitochondria-associated membrane (MAM). Despite the known roles of ER-mitochondria tethering factors like PACS-2 and mitofusin-2, it is not yet entirely clear how they mechanistically interact with the ER environment to determine mitochondrial metabolism. In this article, we review the mechanisms used to communicate ER redox and folding conditions to the mitochondria, presumably with the goal of controlling mitochondrial metabolism at the Krebs cycle and at the electron transport chain, leading to oxidative phosphorylation (OXPHOS). To achieve this goal, redox nanodomains in the ER and the interorganellar cleft influence the activities of ER chaperones and Ca2+-handling proteins to signal to mitochondria. This mechanism, based on ER chaperones like calnexin and ER oxidoreductases like Ero1α, controls reactive oxygen production within the ER, which can chemically modify the proteins controlling ER-mitochondria tethering, or mitochondrial membrane dynamics. It can also lead to the expression of apoptotic or metabolic transcription factors. The link between mitochondrial metabolism and ER homeostasis is evident from the specific functions of mitochondria-ER contact site (MERC)-localized Ire1 and PERK. These functions allow these two transmembrane proteins to act as mitochondria-preserving guardians, a function that is apparently unrelated to their functions in the unfolded protein response (UPR). In scenarios where ER stress cannot be resolved via the activation of mitochondrial OXPHOS, MAM-localized autophagosome formation acts to remove defective portions of the ER. ER chaperones such as calnexin are again critical regulators of this MERC readout.
    Keywords:  ER-phagy; autophagy; chaperones; endoplasmic reticulum; mitochondria; redox
  7. Mol Cancer Res. 2019 Sep 27. pii: molcanres.0540.2019. [Epub ahead of print]
    Herroon MK, Diedrich JD, Rajagurubandara E, Martin C, Maddipati K, Kim S, Heath EI, Granneman J, Podgorski I.
      Adipocyte-tumor cell crosstalk is one of the critical mediators of tumor progression and an emerging facilitator of therapy evasion. Tumor cells that metastasize to adipocyte-rich bone marrow take advantage of the interplay between metabolic and inflammatory pathways to activate pro-survival mechanisms that allow them to thrive and escape therapy. Using in vitro and in vivo models of marrow adiposity, we demonstrate that metastatic prostate carcinoma (PCa) cells engage bone marrow adipocytes in a functional crosstalk that promotes IL-1β expression in tumor cells. Tumor-supplied IL-1β contributes to adipocyte lipolysis and regulates a pro-inflammatory phenotype in adipocytes via upregulation of COX-2 and MCP-1. We further show that the enhanced activity of the IL-1β/COX-2/MCP-1 axis and a resulting increase in PGE2 production by adipocytes coincide with augmented hypoxia signaling and activation of pro-survival pathways in tumor cells, revealing a potential mechanism of chemoresistance. The major consequence of this interplay is the reduced response of PCa cells to docetaxel, a phenomenon sensitive to the inhibition of lipolysis. Implications: Studies presented herein highlight adipocyte lipolysis as a tumor-regulated metabolic event that engages pro-inflammatory crosstalk in the microenvironment to promote PCa progression in bone. Understanding the impact of bone marrow adipose tissue on tumor adaptation, survival and chemotherapy response is fundamentally important, as current treatment options for metastatic PCa are palliative.