bims-camemi Biomed News
on Mitochondrial metabolism in cancer
Issue of 2020‒07‒26
sixty-three papers selected by
Christian Frezza
University of Cambridge, MRC Cancer Unit


  1. Nat Metab. 2020 Jul;2(7): 566-571
    Rabinowitz JD, Enerbäck S.
      Lactate, perhaps the best-known metabolic waste product, was first isolated from sour milk, in which it is produced by lactobacilli. Whereas microbes also generate other fermentation products, such as ethanol or acetone, lactate dominates in mammals. Lactate production increases when the demand for ATP and oxygen exceeds supply, as occurs during intense exercise and ischaemia. The build-up of lactate in stressed muscle and ischaemic tissues has established lactate's reputation as a deleterious waste product. In this Perspective, we summarize emerging evidence that, in mammals, lactate also serves as a major circulating carbohydrate fuel. By providing mammalian cells with both a convenient source and sink for three-carbon compounds, circulating lactate enables the uncoupling of carbohydrate-driven mitochondrial energy generation from glycolysis. Lactate and pyruvate together serve as a circulating redox buffer that equilibrates the NADH/NAD ratio across cells and tissues. This reconceptualization of lactate as a fuel-analogous to how Hans Christian Andersen's ugly duckling is actually a beautiful swan-has the potential to reshape the field of energy metabolism.
    DOI:  https://doi.org/10.1038/s42255-020-0243-4
  2. Clin Endocrinol (Oxf). 2020 Jul 19.
    MacFarlane J, Seong KC, Bisamber C, Madhu B, Allinson K, Marker A, Warren A, Park SM, Giger O, Challis BG, Maher ER, Casey RT.
      The citric acid cycle, also known as the Krebs cycle, plays an integral role in cellular metabolism and aerobic respiration. Mutations in genes encoding the citric acid cycle enzymes succinate dehydrogenase, fumarate hydratase and malate dehydrogenase all predispose to hereditary tumour syndromes. The succinate dehydrogenase enzyme complex (SDH) couples the oxidation of succinate to fumarate in the citric acid cycle and the reduction of ubiquinone to ubiquinol in the electron transport chain. A loss of function in the succinate dehydrogenase (SDH) enzyme complex is most commonly caused by an inherited mutation in one of the four SDHx genes (SDHA, SDHB, SDHC and SDHD). This mechanism was first implicated in familial phaeochromocytoma and paraganglioma. However, over the past two decades the spectrum of tumours associated with SDH deficiency has been extended to include; gastrointestinal stromal tumours (GIST), renal cell carcinoma (RCC) and pituitary adenomas. The aim of this review is to describe the extended tumour spectrum associated with SDHx gene mutations and to consider how functional tests may help to establish the role of SDHx mutations in new or unexpected tumour phenotypes.
    DOI:  https://doi.org/10.1111/cen.14289
  3. Science. 2020 Jul 24. 369(6502): 450-455
    Chen M, Sun H, Boot M, Shao L, Chang SJ, Wang W, Lam TT, Lara-Tejero M, Rego EH, Galán JE.
      The guanosine triphosphatase (GTPase) Rab32 coordinates a cell-intrinsic host defense mechanism that restricts the replication of intravacuolar pathogens such as Salmonella Here, we show that this mechanism requires aconitate decarboxylase 1 (IRG1), which synthesizes itaconate, a metabolite with antimicrobial activity. We find that Rab32 interacts with IRG1 on Salmonella infection and facilitates the delivery of itaconate to the Salmonella-containing vacuole. Mice defective in IRG1 rescued the virulence defect of a S. enterica serovar Typhimurium mutant specifically defective in its ability to counter the Rab32 defense mechanism. These studies provide a link between a metabolite produced in the mitochondria after stimulation of innate immune receptors and a cell-autonomous defense mechanism that restricts the replication of an intracellular bacterial pathogen.
    DOI:  https://doi.org/10.1126/science.aaz1333
  4. Nat Metab. 2020 Jul;2(7): 594-602
    Swain A, Bambouskova M, Kim H, Andhey PS, Duncan D, Auclair K, Chubukov V, Simons DM, Roddy TP, Stewart KM, Artyomov MN.
      Following activation, macrophages undergo extensive metabolic rewiring1,2. Production of itaconate through the inducible enzyme IRG1 is a key hallmark of this process3. Itaconate inhibits succinate dehydrogenase4,5, has electrophilic properties6 and is associated with a change in cytokine production4. Here, we compare the metabolic, electrophilic and immunologic profiles of macrophages treated with unmodified itaconate and a panel of commonly used itaconate derivatives to examine its role. Using wild-type and Irg1-/- macrophages, we show that neither dimethyl itaconate, 4-octyl itaconate nor 4-monoethyl itaconate are converted to intracellular itaconate, while exogenous itaconic acid readily enters macrophages. We find that only dimethyl itaconate and 4-octyl itaconate induce a strong electrophilic stress response, in contrast to itaconate and 4-monoethyl itaconate. This correlates with their immunosuppressive phenotype: dimethyl itaconate and 4-octyl itaconate inhibited IκBζ and pro-interleukin (IL)-1β induction, as well as IL-6, IL-10 and interferon-β secretion, in an NRF2-independent manner. In contrast, itaconate treatment suppressed IL-1β secretion but not pro-IL-1β levels and, surprisingly, strongly enhanced lipopolysaccharide-induced interferon-β secretion. Consistently, Irg1-/- macrophages produced lower levels of interferon and reduced transcriptional activation of this pathway. Our work establishes itaconate as an immunoregulatory, rather than strictly immunosuppressive, metabolite and highlights the importance of using unmodified itaconate in future studies.
    DOI:  https://doi.org/10.1038/s42255-020-0210-0
  5. Nat Metab. 2020 Jul 06.
    Zhu Z, Achreja A, Meurs N, Animasahun O, Owen S, Mittal A, Parikh P, Lo TW, Franco-Barraza J, Shi J, Gunchick V, Sherman MH, Cukierman E, Pickering AM, Maitra A, Sahai V, Morgan MA, Nagrath S, Lawrence TS, Nagrath D.
      Branched-chain amino acids (BCAAs) supply both carbon and nitrogen in pancreatic cancers, and increased levels of BCAAs have been associated with increased risk of pancreatic ductal adenocarcinomas (PDACs). It remains unclear, however, how stromal cells regulate BCAA metabolism in PDAC cells and how mutualistic determinants control BCAA metabolism in the tumour milieu. Here, we show distinct catabolic, oxidative and protein turnover fluxes between cancer-associated fibroblasts (CAFs) and cancer cells, and a marked reliance on branched-chain α-ketoacid (BCKA) in PDAC cells in stroma-rich tumours. We report that cancer-induced stromal reprogramming fuels this BCKA demand. The TGF-β-SMAD5 axis directly targets BCAT1 in CAFs and dictates internalization of the extracellular matrix from the tumour microenvironment to supply amino-acid precursors for BCKA secretion by CAFs. The in vitro results were corroborated with circulating tumour cells (CTCs) and PDAC tissue slices derived from people with PDAC. Our findings reveal therapeutically actionable targets in pancreatic stromal and cancer cells.
    DOI:  https://doi.org/10.1038/s42255-020-0226-5
  6. Nat Metab. 2020 Jul 20.
    Legouis D, Ricksten SE, Faivre A, Verissimo T, Gariani K, Verney C, Galichon P, Berchtold L, Feraille E, Fernandez M, Placier S, Koppitch K, Hertig A, Martin PY, Naesens M, Pugin J, McMahon AP, Cippà PE, de Seigneux S.
      Acute kidney injury (AKI) is strongly associated with mortality, independently of its cause. The kidney contributes to up to 40% of systemic glucose production by gluconeogenesis during fasting and under stress conditions. Whether kidney gluconeogenesis is impaired during AKI and how this might influence systemic metabolism remain unknown. Here we show that glucose production and lactate clearance are impaired during human and experimental AKI by using renal arteriovenous catheterization in patients, lactate tolerance testing in mice and glucose isotope labelling in rats. Single-cell transcriptomics reveal that gluconeogenesis is impaired in proximal tubule cells during AKI. In a retrospective cohort of critically ill patients, we demonstrate that altered glucose metabolism during AKI is a major determinant of systemic glucose and lactate levels and is strongly associated with mortality. Thiamine supplementation increases lactate clearance without modifying renal function in mice with AKI, enhances glucose production by renal tubular cells ex vivo and is associated with reduced mortality and improvement of the metabolic pattern in a retrospective cohort of critically ill patients with AKI. This study highlights an unappreciated systemic role of renal glucose and lactate metabolism under stress conditions, delineates general mechanisms of AKI-associated mortality and introduces a potential intervention targeting metabolism for a highly prevalent clinical condition with limited therapeutic options.
    DOI:  https://doi.org/10.1038/s42255-020-0238-1
  7. Proc Natl Acad Sci U S A. 2020 Jul 23. pii: 202003236. [Epub ahead of print]
    Peng W, Wong YC, Krainc D.
      Mitochondria and lysosomes are critical for cellular homeostasis, and dysfunction of both organelles has been implicated in numerous diseases. Recently, interorganelle contacts between mitochondria and lysosomes were identified and found to regulate mitochondrial dynamics. However, whether mitochondria-lysosome contacts serve additional functions by facilitating the direct transfer of metabolites or ions between the two organelles has not been elucidated. Here, using high spatial and temporal resolution live-cell microscopy, we identified a role for mitochondria-lysosome contacts in regulating mitochondrial calcium dynamics through the lysosomal calcium efflux channel, transient receptor potential mucolipin 1 (TRPML1). Lysosomal calcium release by TRPML1 promotes calcium transfer to mitochondria, which was mediated by tethering of mitochondria-lysosome contact sites. Moreover, mitochondrial calcium uptake at mitochondria-lysosome contact sites was modulated by the outer and inner mitochondrial membrane channels, voltage-dependent anion channel 1 and the mitochondrial calcium uniporter, respectively. Since loss of TRPML1 function results in the lysosomal storage disorder mucolipidosis type IV (MLIV), we examined MLIV patient fibroblasts and found both altered mitochondria-lysosome contact dynamics and defective contact-dependent mitochondrial calcium uptake. Thus, our work highlights mitochondria-lysosome contacts as key contributors to interorganelle calcium dynamics and their potential role in the pathophysiology of disorders characterized by dysfunctional mitochondria or lysosomes.
    Keywords:  TRPML1; calcium; lysosomal storage disorder; mitochondria–lysosome contacts; interorganelle membrane contact sites
    DOI:  https://doi.org/10.1073/pnas.2003236117
  8. Autophagy. 2020 Jul 20.
    He A, Dean JM, Lu D, Chen Y, Lodhi IJ.
      Hepatic lipid homeostasis is controlled by a coordinated regulation of various metabolic pathways involved in de novo synthesis, uptake, storage, and catabolism of lipids. Disruption of this balance could lead to hepatic steatosis. Peroxisomes play an essential role in lipid metabolism, yet their importance is often overlooked. In a recent study, we demonstrated a role for hepatic peroxisomal β-oxidation in autophagic degradation of lipid droplets. ACOX1 (acyl-Coenzyme A oxidase 1, palmitoyl), the rate-limiting enzyme of peroxisomal β-oxidation, increases with fasting or high-fat diet (HFD). Liver-specific acox1 knockout (acox1-LKO) protects mice from hepatic steatosis induced by starvation or HFD via induction of lipophagy. Mechanistically, we showed that hepatic ACOX1 deficiency decreases the total cytosolic acetyl-CoA levels, which leads to reduced acetylation of RPTOR/RAPTOR, a component of MTORC1, which is a key regulator of macroautophagy/autophagy. These results identify peroxisome-derived acetyl-CoA as a critical metabolic regulator of autophagy that controls hepatic lipid homeostasis.
    Keywords:  ACOX1; MTORC1; NAFLD; autophagy; lipids; lipophagy; lysosome; peroxisome
    DOI:  https://doi.org/10.1080/15548627.2020.1797288
  9. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30537-2. [Epub ahead of print]54(2): 239-255
    Nakamura-Ishizu A, Ito K, Suda T.
      Cellular metabolism in hematopoietic stem cells (HSCs) is an area of intense research interest, but the metabolic requirements of HSCs and their adaptations to their niches during development have remained largely unaddressed. Distinctive from other tissue stem cells, HSCs transition through multiple hematopoietic sites during development. This transition requires drastic metabolic shifts, insinuating the capacity of HSCs to meet the physiological demand of hematopoiesis. In this review, we highlight how mitochondrial metabolism determines HSC fate, and especially focus on the links between mitochondria, endoplasmic reticulum (ER), and lysosomes in HSC metabolism.
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.029
  10. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30538-4. [Epub ahead of print]54(2): 268-281
    Sebastián D, Zorzano A.
      Cellular processes that sense and transmit metabolic changes are crucial for adaptation to external signals. In this regard, autophagy provides energy upon nutrient deprivation and represents a quality control mechanism that eliminates damaged organelles or proteins. Here, we review recent findings on the metabolic pathways controlling autophagy in skeletal muscle, a plastic tissue that undergoes major changes in energy demands. We also analyze the implications of autophagy in the regulation of energy metabolism in muscle and how alterations in this process affect energy homeostasis at the whole-body level and the development of metabolic diseases and aging.
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.030
  11. Front Oncol. 2020 ;10 1053
    Koit A, Timohhina N, Truu L, Chekulayev V, Gudlawar S, Shevchuk I, Lepik K, Mallo L, Kutner R, Valvere V, Kaambre T.
      Research on mitochondrial metabolism and respiration are rapidly developing areas, however, efficient and widely accepted methods for studying these in solid tumors are still missing. Here, we developed a new method without isotope tracing to quantitate time dependent mitochondrial citrate efflux in cell lines and human breast cancer samples. In addition, we studied ADP-activated respiration in both of the sample types using selective permeabilization and showed that metabolic activity and respiration are not equally linked. Three times lower amount of mitochondria in scarcely respiring MDA-MB-231 cells convert pyruvate and glutamate into citrate efflux at 20% higher rate than highly respiring MCF-7 mitochondria do. Surprisingly, analysis of 59 human breast cancers revealed the opposite in clinical samples as aggressive breast cancer subtypes, in comparison to less aggressive subtypes, presented with both higher mitochondrial citrate efflux and higher respiration rate. Additionally, comparison of substrate preference (pyruvate or glutamate) for both mitochondrial citrate efflux and respiration in triple negative breast cancers revealed probable causes for high glutamine dependence in this subtype and reasons why some of these tumors are able to overcome glutaminase inhibition. Our research concludes that the two widely used breast cancer cell lines fail to replicate mitochondrial function as seen in respective human samples. And finally, the easy method described here, where time dependent small molecule metabolism and ADP-activated respiration in solid human cancers are analyzed together, can increase success of translational research and ultimately benefit patients with cancer.
    Keywords:  ADP-activated respiration; OXPHOS; cancer metabolism; citrate; glutaminolysis; metabolic dependencies; mitochondrial flux; predictive biomarker
    DOI:  https://doi.org/10.3389/fonc.2020.01053
  12. Cancer Discov. 2020 Jul 20.
    Carbone M, Harbour JW, Brugarolas J, Bononi A, Pagano I, Dey A, Krausz T, Pass HI, Yang H, Gaudino G.
      Among more than 200 BAP1-mutant families affected by the "BAP1 cancer syndrome," nearly all individuals inheriting a BAP1 mutant allele developed one or more malignancies during their lifetime, mostly uveal and cutaneous melanoma, mesothelioma, and clear-cell renal cell carcinoma. These cancer types are also those that, when they occur sporadically, are more likely to carry somatic biallelic BAP1 mutations. Mechanistic studies revealed that the tumor suppressor function of BAP1 is linked to its dual activity in the nucleus, where it is implicated in a variety of processes including DNA repair and transcription, and in the cytoplasm, where it regulates cell death and mitochondrial metabolism. BAP1 activity in tumor suppression is cell type- and context-dependent. BAP1 has emerged as a critical tumor suppressor across multiple cancer types, predisposing to tumor development when mutated in the germline as well as somatically. Moreover, BAP1 has emerged as a key regulator of gene-environment interaction.
    DOI:  https://doi.org/10.1158/2159-8290.CD-19-1220
  13. Nat Metab. 2020 Jul;2(7): 635-647
    Wang T, Gnanaprakasam JNR, Chen X, Kang S, Xu X, Sun H, Liu L, Rodgers H, Miller E, Cassel TA, Sun Q, Vicente-Muñoz S, Warmoes MO, Lin P, Piedra-Quintero ZL, Guerau-de-Arellano M, Cassady KA, Zheng SG, Yang J, Lane AN, Song X, Fan TW, Wang R.
      T cells undergo metabolic rewiring to meet their bioenergetic, biosynthetic and redox demands following antigen stimulation. To fulfil these needs, effector T cells must adapt to fluctuations in environmental nutrient levels at sites of infection and inflammation. Here, we show that effector T cells can utilize inosine, as an alternative substrate, to support cell growth and function in the absence of glucose in vitro. T cells metabolize inosine into hypoxanthine and phosphorylated ribose by purine nucleoside phosphorylase. We demonstrate that the ribose subunit of inosine can enter into central metabolic pathways to provide ATP and biosynthetic precursors, and that cancer cells display diverse capacities to utilize inosine as a carbon source. Moreover, the supplementation with inosine enhances the anti-tumour efficacy of immune checkpoint blockade and adoptive T-cell transfer in solid tumours that are defective in metabolizing inosine, reflecting the capability of inosine to relieve tumour-imposed metabolic restrictions on T cells.
    DOI:  https://doi.org/10.1038/s42255-020-0219-4
  14. Mol Pharm. 2020 Jul 21.
    Prag HA, Kula-Alwar D, Pala L, Caldwell ST, Beach TE, James AM, Saeb-Parsy K, Krieg T, Hartley RC, Murphy MP.
      Many mitochondrial metabolites and bioactive molecules contain two carboxylic acid moieties that make them unable to cross biological membranes. Hence, there is considerable interest in facilitating the uptake of these molecules into cells and mitochondria, to modify or report on their function. Conjugation to the triphenylphosphonium (TPP) lipophilic cation is widely used to deliver molecules selectively to mitochondria in response to the membrane potential. However, permanent attachment to the cation can disrupt the biological function of small dicarboxylates. Here, we have developed a strategy using TPP to release dicarboxylates selectively within mitochondria. For this the dicarboxylate is attached to a TPP via a single ester bond which is then cleaved by intra-mitochondrial esterase activity, releasing the dicarboxylate within the organelle. Leaving the second carboxylic acid free also means mitochondrial uptake is dependent on the pH gradient across the inner membrane. To assess this strategy, we synthesized a range of TPP monoesters of the model dicarboxylate, malonate. We then tested their mitochondrial accumulation and ability to deliver malonate to isolated mitochondria, and to cells in vitro and in vivo. A TPP-malonate monoester, TPP11-malonate, in which the dicarboxylate was attached to the TPP via a hydrophobic undecyl link was most effective at releasing malonate within mitochondria in cells and in vivo. Therefore, we have developed a TPP-monoester platform that enables the selective release of bioactive dicarboxylates within mitochondria.
    DOI:  https://doi.org/10.1021/acs.molpharmaceut.0c00533
  15. Oncogene. 2020 Jul 21.
    Kohno S, Linn P, Nagatani N, Watanabe Y, Kumar S, Soga T, Takahashi C.
      RB1 gene is often homozygously deleted or mutated in prostate adenocarcinomas following acquirement of castration resistance and/or metastatic ability. We found that SUCLA2 gene is frequently involved in the deletion of the RB1 gene region in advanced prostate cancer. SUCLA2 constitutes the β-subunit of succinate CoA ligase heterodimer that reversibly converts succinyl CoA into succinate. We sought the possibility that deletion of SUCLA2 gives rise to a metabolic vulnerability that could be targeted therapeutically. We found a significant metabolic shift in SUCLA2-deleted prostate cancer cells, including lower mitochondrial respiratory activity. By screening a number of libraries for compounds that induce cell death selectively in SUCLA2-deficient prostate cancer cells, we identified thymoquinone (2-isopropyl-5-methylbenzo-1,4-quinone) and PMA (phorbol-12-myristate-13-acetate) from a natural compound library. These findings indicate that the metabolic vulnerability in SUCLA2-deficient prostate cancer cells is pharmacologically targetable.
    DOI:  https://doi.org/10.1038/s41388-020-1381-6
  16. Nat Metab. 2020 Jul;2(7): 603-611
    Carlisle AE, Lee N, Matthew-Onabanjo AN, Spears ME, Park SJ, Youkana D, Doshi MB, Peppers A, Li R, Joseph AB, Smith M, Simin K, Zhu LJ, Greer PL, Shaw LM, Kim D.
      The micronutrient selenium is incorporated via the selenocysteine biosynthesis pathway into the rare amino acid selenocysteine, which is required in selenoproteins such as glutathione peroxidases and thioredoxin reductases1,2. Here, we show that selenophosphate synthetase 2 (SEPHS2), an enzyme in the selenocysteine biosynthesis pathway, is essential for survival of cancer, but not normal, cells. SEPHS2 is required in cancer cells to detoxify selenide, an intermediate that is formed during selenocysteine biosynthesis. Breast and other cancer cells are selenophilic, owing to a secondary function of the cystine/glutamate antiporter SLC7A11 that promotes selenium uptake and selenocysteine biosynthesis, which, by allowing production of selenoproteins such as GPX4, protects cells against ferroptosis. However, this activity also becomes a liability for cancer cells because selenide is poisonous and must be processed by SEPHS2. Accordingly, we find that SEPHS2 protein levels are elevated in samples from people with breast cancer, and that loss of SEPHS2 impairs growth of orthotopic mammary-tumour xenografts in mice. Collectively, our results identify a vulnerability of cancer cells and define the role of selenium metabolism in cancer.
    DOI:  https://doi.org/10.1038/s42255-020-0224-7
  17. Oncogene. 2020 Jul 24.
    Lee N, Spears ME, Carlisle AE, Kim D.
      It is well recognized that many metabolic enzymes play essential roles in cancer cells in producing building blocks such as nucleotides, which are required in greater amounts due to their increased proliferation. On the other hand, the significance of enzymes in preventing the accumulation of their substrates is less recognized. Here, we outline the evidence and underlying mechanisms for how many metabolites normally produced in cells are highly toxic, such as metabolites containing reactive groups (e.g., methylglyoxal, 4-hydroxynonenal, and glutaconyl-CoA), or metabolites that act as competitive analogs against other metabolites (e.g., deoxyuridine triphosphate and l-2-hydroxyglutarate). Thus, if a metabolic pathway contains a toxic intermediate, then we may be able to induce accumulation and poison a cancer cell by targeting the downstream enzyme. Furthermore, this poisoning may be cancer cell selective if this pathway is overactive in a cancer cell relative to a nontransformed cell. We describe this concept as illustrated in selenocysteine metabolism and other pathways and discuss future directions in exploiting toxic metabolites to kill cancer cells.
    DOI:  https://doi.org/10.1038/s41388-020-01395-9
  18. Cancer Discov. 2020 Jul 20. pii: CD-20-0288. [Epub ahead of print]
    Liao C, Zhang Y, Fan C, Herring LE, Liu J, Locasale JW, Takada M, Zhou J, Zurlo G, Hu L, Simon JM, Ptacek TS, Andrianov VG, Loza E, Peng Y, Yang H, Perou CM, Zhang Q.
      Triple-negative breast cancer (TNBC) is an aggressive and highly lethal disease. Due to its heterogeneity and lack of hormone receptors or HER2 expression, targeted therapy is limited. Here, by performing a functional siRNA screening for 2-OG-dependent enzymes, we identified gamma-butyrobetaine hydroxylase 1 (BBOX1) as an essential gene for TNBC tumorigenesis. BBOX1 depletion inhibits TNBC cell growth, while not affecting normal breast cells. Mechanistically, BBOX1 binds with the calcium channel inositol-1,4,5-trisphosphate receptor type 3 (IP3R3) in an enzymatic-dependent manner and prevents its ubiquitination and proteasomal degradation. BBOX1 depletion suppresses IP3R3 mediated endoplasmic reticulum calcium release, therefore impairing calcium-dependent energy-generating processes including mitochondrial respiration and mTORC1 mediated glycolysis, which leads to apoptosis and impaired cell cycle progression in TNBC cells. Therapeutically, genetic depletion or pharmacological inhibition of BBOX1 inhibits TNBC tumor growth in vitro and in vivo. Our study highlights the importance of targeting previously uncharacterized BBOX1-IP3R3-calcium oncogenic signaling axis in TNBC.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0288
  19. Biomolecules. 2020 Jul 17. pii: E1068. [Epub ahead of print]10(7):
    Zangari J, Petrelli F, Maillot B, Martinou JC.
      Pyruvate, the end product of glycolysis, plays a major role in cell metabolism. Produced in the cytosol, it is oxidized in the mitochondria where it fuels the citric acid cycle and boosts oxidative phosphorylation. Its sole entry point into mitochondria is through the recently identified mitochondrial pyruvate carrier (MPC). In this review, we report the latest findings on the physiology of the MPC and we discuss how a dysfunctional MPC can lead to diverse pathologies, including neurodegenerative diseases, metabolic disorders, and cancer.
    Keywords:  cancer; metabolic disorders; metabolism; mitochondria; mitochondrial pyruvate carrier; neurodegeneration
    DOI:  https://doi.org/10.3390/biom10071068
  20. iScience. 2020 Jul 03. pii: S2589-0042(20)30525-3. [Epub ahead of print]23(7): 101338
    Vaughan ME, Wallace M, Handzlik MK, Chan AB, Metallo CM, Lamia KA.
      Muscles preferentially utilize glycolytic or oxidative metabolism depending on the intensity of physical activity. Transcripts required for carbohydrate and lipid metabolism undergo circadian oscillations of expression in muscles, and both exercise capacity and the metabolic response to exercise are influenced by time of day. The circadian repressors CRY1 and CRY2 repress peroxisome proliferator-activated receptor delta (PPARδ), a major driver of oxidative metabolism and exercise endurance. CRY-deficient mice exhibit enhanced PPARδ activation and greater maximum speed when running on a treadmill but no increase in exercise endurance. Here we demonstrate that CRYs limit hypoxia-responsive transcription via repression of HIF1α-BMAL1 heterodimers. Furthermore, CRY2 appeared to be more effective than CRY1 in the reduction of HIF1α protein steady-state levels in primary myotubes and quadriceps in vivo. Finally, CRY-deficient myotubes exhibit metabolic alterations consistent with cryptochrome-dependent suppression of HIF1α, which likely contributes to circadian modulation of muscle metabolism.
    Keywords:  Cell Biology; Chronobiology
    DOI:  https://doi.org/10.1016/j.isci.2020.101338
  21. Nat Metab. 2020 Jul 20.
    Chen Z, Miao F, Braffett BH, Lachin JM, Zhang L, Wu X, Roshandel D, Carless M, Li XA, Tompkins JD, Kaddis JS, Riggs AD, Paterson AD, , Natarajan R.
      Metabolic memory, the persistent benefits of early glycaemic control on preventing and/or delaying the development of diabetic complications, has been observed in the Diabetes Control and Complications Trial (DCCT) and in the Epidemiology of Diabetes Interventions and Complications (EDIC) follow-up study, but the underlying mechanisms remain unclear. Here, we show the involvement of epigenetic DNA methylation (DNAme) in metabolic memory by examining its associations with preceding glycaemic history, and with subsequent development of complications over an 18-yr period in the blood DNA of 499 randomly selected DCCT participants with type 1 diabetes who are also followed up in EDIC. We demonstrate the associations between DNAme near the closeout of DCCT and mean HbA1c during DCCT (mean-DCCT HbA1c) at 186 cytosine-guanine dinucleotides (CpGs) (FDR < 15%, including 43 at FDR < 5%), many of which were located in genes related to complications. Exploration studies into biological function reveal that these CpGs are enriched in binding sites for the C/EBP transcription factor, as well as enhancer/transcription regions in blood cells and haematopoietic stem cells, and open chromatin states in myeloid cells. Mediation analyses show that, remarkably, several CpGs in combination explain 68-97% of the association of mean-DCCT HbA1c with the risk of complications during EDIC. In summary, DNAme at key CpGs appears to mediate the association between hyperglycaemia and complications in metabolic memory, through modifying enhancer activity at myeloid and other cells.
    DOI:  https://doi.org/10.1038/s42255-020-0231-8
  22. Nat Commun. 2020 Jul 21. 11(1): 3653
    Schiffmann LM, Werthenbach JP, Heintges-Kleinhofer F, Seeger JM, Fritsch M, Günther SD, Willenborg S, Brodesser S, Lucas C, Jüngst C, Albert MC, Schorn F, Witt A, Moraes CT, Bruns CJ, Pasparakis M, Krönke M, Eming SA, Coutelle O, Kashkar H.
      The vasculature represents a highly plastic compartment, capable of switching from a quiescent to an active proliferative state during angiogenesis. Metabolic reprogramming in endothelial cells (ECs) thereby is crucial to cover the increasing cellular energy demand under growth conditions. Here we assess the impact of mitochondrial bioenergetics on neovascularisation, by deleting cox10 gene encoding an assembly factor of cytochrome c oxidase (COX) specifically in mouse ECs, providing a model for vasculature-restricted respiratory deficiency. We show that EC-specific cox10 ablation results in deficient vascular development causing embryonic lethality. In adult mice induction of EC-specific cox10 gene deletion produces no overt phenotype. However, the angiogenic capacity of COX-deficient ECs is severely compromised under energetically demanding conditions, as revealed by significantly delayed wound-healing and impaired tumour growth. We provide genetic evidence for a requirement of mitochondrial respiration in vascular endothelial cells for neoangiogenesis during development, tissue repair and cancer.
    DOI:  https://doi.org/10.1038/s41467-020-17472-2
  23. J Physiol. 2020 Jul 25.
    Li LY, Lv HB, Jiang ZY, Qiao F, Chen LQ, Zhang ML, Du ZY.
      KEY POINTS: The pparab subtype in zebrafish is much more highly expressed in tissues with high oxidative activity than pparaa. The pparab deficiency in zebrafish reduces FAO both in liver and muscle, illustrating its functional homology as mammalian PPARα. The pparab deficiency promotes metabolic reprogramming by increasing glucose utilization and inhibiting amino acid breakdown. Our study brings new insights into the comprehensive regulatory roles of PPARα in the cellular fuel selection and provides a valuable animal model for PPARα studies from a viewpoint of comparative physiology.ABSTRACT: Dysfunction of lipid metabolism is involved in the pathogenesis of several chronic metabolic diseases. Peroxisome proliferator-activated receptor α (PPARα) is essential for normal metabolic homeostasis, and in particular for the regulation of fatty acid β-oxidation (FAO). However, little is known about its regulation roles in systemic nutrient metabolism. To explore the underlying modulation role of PPARα in metabolic homeostasis, we generated a pparab-knockout zebrafish (Danio rerio) model. The pparab mutants demonstrated lower expression of key enzymes involved in FAO, and lower mitochondrial and peroxisomal FAO in tissues, which was associated with lipid accumulation in liver and visceral mass. Conversely, glucose utilization was higher, because they demonstrated lower blood glucose and tissue glycogen concentrations, and activation of the phosphoinositide 3-kinase/AKT pathway. In addition, the pparab-deficient zebrafish demonstrated activation of AKT/mammalian target of rapamycin (mTOR) signalling and higher protein content, implying greater protein synthesis and/or lower amino acid breakdown. These data clearly revealed that pparab deletion reduces FAO, but increases glucose utilization and protein deposition, to maintain energy homeostasis. This study provides new insights into the comprehensive regulatory role of PPARα in systemic energy metabolism in fish, and this pparab-deficient zebrafish also constitutes a valuable model for studying the functions of PPARα in mammals from comparative physiology aspects. This article is protected by copyright. All rights reserved.
    Keywords:  PPARα; fatty acid β-oxidation; glucose utilization; lipid homeostasis; metabolic reprogramming; protein deposition; zebrafish
    DOI:  https://doi.org/10.1113/JP279814
  24. Science. 2020 Jul 24. 369(6502): 397-403
    Xu Y, Zhang Y, García-Cañaveras JC, Guo L, Kan M, Yu S, Blair IA, Rabinowitz JD, Yang X.
      Embryonic stem cells can propagate indefinitely in a pluripotent state, able to differentiate into all types of specialized cells when restored to the embryo. What sustains their pluripotency during propagation remains unclear. Here, we show that core pluripotency factors OCT4 and SOX2 suppress chaperone-mediated autophagy (CMA), a selective form of autophagy, until the initiation of differentiation. Low CMA activity promotes embryonic stem cell self-renewal, whereas its up-regulation enhances differentiation. CMA degrades isocitrate dehydrogenases IDH1 and IDH2 and reduces levels of intracellular α-ketoglutarate, an obligatory cofactor for various histone and DNA demethylases involved in pluripotency. These findings suggest that CMA mediates the effect of core pluripotency factors on metabolism, shaping the epigenetic landscape of stem cells and governing the balance between self-renewal and differentiation.
    DOI:  https://doi.org/10.1126/science.abb4467
  25. Cancer Cell. 2020 Jul 08. pii: S1535-6108(20)30316-0. [Epub ahead of print]
    Marjanovic ND, Hofree M, Chan JE, Canner D, Wu K, Trakala M, Hartmann GG, Smith O, Kim J, Evans KV, Hudson A, Ashenberg O, Porter CBM, Bejnood A, Subramanian A, Pitter K, Yan Y, Delroy T, Phillips DR, Shah N, Chaudhary O, Tsankov A, Hollmann T, Rekhtman N, Massion PP, Poirier JT, Mazutis L, Li R, Lee JH, Amon A, Rudin CM, Jacks T, Regev A, Tammela T.
      Tumor evolution from a single cell into a malignant, heterogeneous tissue remains poorly understood. Here, we profile single-cell transcriptomes of genetically engineered mouse lung tumors at seven stages, from pre-neoplastic hyperplasia to adenocarcinoma. The diversity of transcriptional states increases over time and is reproducible across tumors and mice. Cancer cells progressively adopt alternate lineage identities, computationally predicted to be mediated through a common transitional, high-plasticity cell state (HPCS). Accordingly, HPCS cells prospectively isolated from mouse tumors and human patient-derived xenografts display high capacity for differentiation and proliferation. The HPCS program is associated with poor survival across human cancers and demonstrates chemoresistance in mice. Our study reveals a central principle underpinning intra-tumoral heterogeneity and motivates therapeutic targeting of the HPCS.
    Keywords:  cell state transition; lung cancer; plasticity; single-cell transcriptomics; tumor evolution; tumor heterogeneity
    DOI:  https://doi.org/10.1016/j.ccell.2020.06.012
  26. Nat Commun. 2020 Jul 24. 11(1): 3701
    Aubert L, Nandagopal N, Steinhart Z, Lavoie G, Nourreddine S, Berman J, Saba-El-Leil MK, Papadopoli D, Lin S, Hart T, Macleod G, Topisirovic I, Gaboury L, Fahrni CJ, Schramek D, Meloche S, Angers S, Roux PP.
      Despite its importance in human cancers, including colorectal cancers (CRC), oncogenic KRAS has been extremely challenging to target therapeutically. To identify potential vulnerabilities in KRAS-mutated CRC, we characterize the impact of oncogenic KRAS on the cell surface of intestinal epithelial cells. Here we show that oncogenic KRAS alters the expression of a myriad of cell-surface proteins implicated in diverse biological functions, and identify many potential surface-accessible therapeutic targets. Cell surface-based loss-of-function screens reveal that ATP7A, a copper-exporter upregulated by mutant KRAS, is essential for neoplastic growth. ATP7A is upregulated at the surface of KRAS-mutated CRC, and protects cells from excess copper-ion toxicity. We find that KRAS-mutated cells acquire copper via a non-canonical mechanism involving macropinocytosis, which appears to be required to support their growth. Together, these results indicate that copper bioavailability is a KRAS-selective vulnerability that could be exploited for the treatment of KRAS-mutated neoplasms.
    DOI:  https://doi.org/10.1038/s41467-020-17549-y
  27. Nat Commun. 2020 Jul 20. 11(1): 3645
    Elbaz-Alon Y, Guo Y, Segev N, Harel M, Quinnell DE, Geiger T, Avinoam O, Li D, Nunnari J.
      Endosomes are compositionally dynamic organelles that regulate signaling, nutrient status and organelle quality by specifying whether material entering the cells will be shuttled back to the cell surface or degraded by the lysosome. Recently, membrane contact sites (MCSs) between the endoplasmic reticulum (ER) and endosomes have emerged as important players in endosomal protein sorting, dynamics and motility. Here, we show that PDZD8, a Synaptotagmin-like Mitochondrial lipid-binding Proteins (SMP) domain-containing ER transmembrane protein, utilizes distinct domains to interact with Rab7-GTP and the ER transmembrane protein Protrudin and together these components localize to an ER-late endosome MCS. At these ER-late endosome MCSs, mitochondria are also recruited to form a three-way contact. Thus, our data indicate that PDZD8 is a shared component of two distinct MCSs and suggest a role for SMP-mediated lipid transport in the regulation of endosome function.
    DOI:  https://doi.org/10.1038/s41467-020-17451-7
  28. J Physiol. 2020 Jul 25.
    Rudler DL, Hughes LA, Viola HM, Hool LC, Rackham O, Filipovska A.
      The evolutionary acquisition of mitochondria has given rise to the diversity of eukaryotic life. Mitochondria have retained their ancestral α-proteobacterial traits through the maintenance of double membranes and their own circular genome that varies in size, ranging from very large in plants to the smallest in animals and their parasites. The mitochondrial genome encodes essential genes for protein synthesis and has to coordinate its expression with the nuclear genome from which it sources most of the proteins required for mitochondrial biogenesis and function. The mitochondrial protein synthesis machinery is unique because it is encoded by both the nuclear and mitochondrial genome thereby requiring tight regulation to produce the respiratory complexes that drive oxidative phosphorylation for energy production. The fidelity and coordination of mitochondrial protein synthesis are essential for ATP production. Here we compare and contrast the mitochondrial translation mechanisms in mammals and fungi to bacteria and reveal that their diverse regulation can have unusual impacts on the health and disease of these organisms. We highlight that in mammals the rate of protein synthesis is more important than the fidelity of translation, enabling coordinated biogenesis of the mitochondrial respiratory chain with respiratory chain proteins synthesised by cytoplasmic ribosomes. Changes in mitochondrial protein fidelity can trigger the activation of the diverse cellular signalling networks in fungi and mammals to combat dysfunction in energy conservation. The physiological consequences of altered fidelity of protein synthesis can range from liver regeneration to the onset and development of cardiomyopathy. This article is protected by copyright. All rights reserved.
    Keywords:  mitochondria; protein synthesis; ribosomes
    DOI:  https://doi.org/10.1113/JP280359
  29. Cancer Discov. 2020 Jul 24.
      The ability of mitochondrial complex III to oxidize ubiquinol was essential to tumor growth in vivo.
    DOI:  https://doi.org/10.1158/2159-8290.CD-RW2020-107
  30. Nat Metab. 2020 Jul;2(7): 586-593
    Jang C, Wada S, Yang S, Gosis B, Zeng X, Zhang Z, Shen Y, Lee G, Arany Z, Rabinowitz JD.
      Per capita fructose consumption has increased 100-fold over the last century1. Epidemiological studies suggest that excessive fructose consumption, and especially consumption of sweet drinks, is associated with hyperlipidaemia, non-alcoholic fatty liver disease, obesity and diabetes2-7. Fructose metabolism begins with its phosphorylation by the enzyme ketohexokinase (KHK), which exists in two alternatively spliced forms8. The more active isozyme, KHK-C, is expressed most strongly in the liver, but also substantially in the small intestine9,10 where it drives dietary fructose absorption and conversion into other metabolites before fructose reaches the liver11-13. It is unclear whether intestinal fructose metabolism prevents or contributes to fructose-induced lipogenesis and liver pathology. Here we show that intestinal fructose catabolism mitigates fructose-induced hepatic lipogenesis. In mice, intestine-specific KHK-C deletion increases dietary fructose transit to the liver and gut microbiota and sensitizes mice to fructose's hyperlipidaemic effects and hepatic steatosis. In contrast, intestine-specific KHK-C overexpression promotes intestinal fructose clearance and decreases fructose-induced lipogenesis. Thus, intestinal fructose clearance capacity controls the rate at which fructose can be safely ingested. Consistent with this, we show that the same amount of fructose is more strongly lipogenic when drunk than eaten, or when administered as a single gavage, as opposed to multiple doses spread over 45 min. Collectively, these data demonstrate that fructose induces lipogenesis when its dietary intake rate exceeds the intestinal clearance capacity. In the modern context of ready food availability, the resulting fructose spillover drives metabolic syndrome. Slower fructose intake, tailored to intestinal capacity, can mitigate these consequences.
    DOI:  https://doi.org/10.1038/s42255-020-0222-9
  31. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30544-X. [Epub ahead of print]54(2): 156-170
    Figlia G, Willnow P, Teleman AA.
      Metabolites affect cell growth in two different ways. First, they serve as building blocks for biomass accumulation. Second, metabolites regulate the activity of growth-relevant signaling pathways. They do so in part by covalently attaching to proteins, thereby generating post-translational modifications (PTMs) that affect protein function, the focus of this Perspective. Recent advances in mass spectrometry have revealed a wide variety of such metabolites, including lipids, amino acids, Coenzyme-A, acetate, malonate, and lactate to name a few. An active area of research is to understand which modifications affect protein function and how they do so. In many cases, the cellular levels of these metabolites affect the stoichiometry of the corresponding PTMs, providing a direct link between cell metabolism and the control of cell signaling, transcription, and cell growth.
    Keywords:  O-GlcNAc; YAP; acetylation; autophagy; crotonylation; glutathionylation; hippo; mTORC1; malonylation; methylation; palmitoylation
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.036
  32. Annu Rev Cell Dev Biol. 2020 Jul 21.
    Maciejowski J, Hatch EM.
      The nuclear envelope is often depicted as a static barrier that regulates access between the nucleus and the cytosol. However, recent research has identified many conditions in cultured cells and in vivo in which nuclear membrane ruptures cause the loss of nuclear compartmentalization. These conditions include some that are commonly associated with human disease, such as migration of cancer cells through small spaces and expression of nuclear lamin disease mutations in both cultured cells and tissues undergoing nuclear migration. Nuclear membrane ruptures are rapidly repaired in the nucleus but persist in nuclear compartments that form around missegregated chromosomes called micronuclei. This review summarizes what is known about the mechanisms of nuclear membrane rupture and repair in both the main nucleus and micronuclei, and highlights recent work connecting the loss of nuclear integrity to genome instability and innate immune signaling. These connections link nuclear membrane rupture to complex chromosome alterations, tumorigenesis, and laminopathy etiologies. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 36 is October 6, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
    DOI:  https://doi.org/10.1146/annurev-cellbio-020520-120627
  33. Nat Metab. 2020 Jul 13.
    Mi Z, Song Y, Cao X, Lu Y, Liu Z, Zhu X, Geng M, Sun Y, Lan B, He C, Xiong H, Zhang L, Chen Y.
      Metabolic reprogramming is emerging as a key pathological contributor to the progression of autosomal dominant polycystic kidney disease (ADPKD), but the molecular mechanisms underlying dysregulated cellular metabolism in cystic cells remain elusive. Super-enhancers (SEs) are large clusters of transcriptional enhancers that drive robust expression of cell identity and disease genes. Here, we show that SEs undergo extensive remodelling during cystogenesis and that SE-associated transcripts are most enriched for metabolic processes in cystic cells. Inhibition of cyclin-dependent kinase 7 (CDK7), a transcriptional kinase required for assembly and maintenance of SEs, or AMP deaminase 3 (AMPD3), one of the SE-driven and CDK7-controlled metabolic target genes, delays cyst growth in ADPKD mouse models. In a cohort of people with ADPKD, CDK7 expression was frequently elevated, and its expression was correlated with AMPD3 expression and disease severity. Together, our findings elucidate a mechanism by which SE controls transcription of metabolic genes during cystogenesis, and identify SE-driven metabolic reprogramming as a promising therapeutic target for ADPKD treatment.
    DOI:  https://doi.org/10.1038/s42255-020-0227-4
  34. Elife. 2020 Jul 21. pii: e56580. [Epub ahead of print]9
    Jenkins NL, James SA, Salim A, Sumardy F, Speed TP, Conrad M, Richardson DR, Bush AI, McColl G.
      All eukaryotes require iron. Replication, detoxification, and a cancer-protective form of regulated cell death termed ferroptosis, all depend on iron metabolism. Ferrous iron accumulates over adult lifetime in Caenorhabditis elegans. Here, we show that glutathione depletion is coupled to ferrous iron elevation in these animals, and that both occur in late life to prime cells for ferroptosis. We demonstrate that blocking ferroptosis, either by inhibition of lipid peroxidation or by limiting iron retention, mitigates age-related cell death and markedly increases lifespan and healthspan. Temporal scaling of lifespan is not evident when ferroptosis is inhibited, consistent with this cell death process acting at specific life phases to induce organismal frailty, rather than contributing to a constant aging rate. Because excess age-related iron elevation in somatic tissue, particularly in brain, is thought to contribute to degenerative disease, post-developmental interventions to limit ferroptosis may promote healthy aging.
    Keywords:  C. elegans; biochemistry; chemical biology; ferroptosis; fitness; frailty; glutathione; iron; lifespan
    DOI:  https://doi.org/10.7554/eLife.56580
  35. Nature. 2020 Jul 22.
    Chan LN, Murakami MA, Robinson ME, Caeser R, Sadras T, Lee J, Cosgun KN, Kume K, Khairnar V, Xiao G, Ahmed MA, Aghania E, Deb G, Hurtz C, Shojaee S, Hong C, Pölönen P, Nix MA, Chen Z, Chen CW, Chen J, Vogt A, Heinäniemi M, Lohi O, Wiita AP, Izraeli S, Geng H, Weinstock DM, Müschen M.
      Malignant transformation of cells typically involves several genetic lesions, whose combined activity gives rise to cancer1. Here we analyse 1,148 patient-derived B-cell leukaemia (B-ALL) samples, and find that individual mutations do not promote leukaemogenesis unless they converge on one single oncogenic pathway that is characteristic of the differentiation stage of transformed B cells. Mutations that are not aligned with this central oncogenic driver activate divergent pathways and subvert transformation. Oncogenic lesions in B-ALL frequently mimic signalling through cytokine receptors at the pro-B-cell stage (via activation of the signal-transduction protein STAT5)2-4 or pre-B-cell receptors in more mature cells (via activation of the protein kinase ERK)5-8. STAT5- and ERK-activating lesions are found frequently, but occur together in only around 3% of cases (P = 2.2 × 10-16). Single-cell mutation and phospho-protein analyses reveal the segregation of oncogenic STAT5 and ERK activation to competing clones. STAT5 and ERK engage opposing biochemical and transcriptional programs that are orchestrated by the transcription factors MYC and BCL6, respectively. Genetic reactivation of the divergent (suppressed) pathway comes at the expense of the principal oncogenic driver and reverses transformation. Conversely, deletion of divergent pathway components accelerates leukaemogenesis. Thus, persistence of divergent signalling pathways represents a powerful barrier to transformation, while convergence on one principal driver defines a central event in leukaemia initiation. Pharmacological reactivation of suppressed divergent circuits synergizes strongly with inhibition of the principal oncogenic driver. Hence, reactivation of divergent pathways can be leveraged as a previously unrecognized strategy to enhance treatment responses.
    DOI:  https://doi.org/10.1038/s41586-020-2513-4
  36. Cell Res. 2020 Jul 24.
    Shyer JA, Flavell RA, Bailis W.
      The maintenance of organismal homeostasis requires partitioning and transport of biochemical molecules between organ systems, their composite cells, and subcellular organelles. Although transcriptional programming undeniably defines the functional state of cells and tissues, underlying biochemical networks are intricately intertwined with transcriptional, translational, and post-translational regulation. Studies of the metabolic regulation of immunity have elegantly illustrated this phenomenon. The cells of the immune system interface with a diverse set of environmental conditions. Circulating immune cells perfuse peripheral organs in the blood and lymph, patrolling for pathogen invasion. Resident immune cells remain in tissues and play more newly appreciated roles in tissue homeostasis and immunity. Each of these cell populations interacts with unique and dynamic tissue environments, which vary greatly in biochemical composition. Furthermore, the effector response of immune cells to a diverse set of activating cues requires unique cellular adaptations to supply the requisite biochemical landscape. In this review, we examine the role of spatial partitioning of metabolic processes in immune function. We focus on studies of lymphocyte metabolism, with reference to the greater immunometabolism literature when appropriate to illustrate this concept.
    DOI:  https://doi.org/10.1038/s41422-020-0379-5
  37. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30502-5. [Epub ahead of print]54(2): 137-139
    Castro M, Andrade J, Potente M.
      Blood vessels are an essential interface between the circulation and tissue that deploy signaling molecules (angiocrines) for organ development, homeostasis, and repair. In a recent issue of Cell Metabolism, Zhang et al. (2020) identify lactate as an endothelial-derived signal promoting ischemic muscle regeneration, establishing metabolites as a new angiocrine class.
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.023
  38. Nat Rev Nephrol. 2020 Jul 23.
    Tang C, Livingston MJ, Liu Z, Dong Z.
      Autophagy is a conserved lysosomal pathway for the degradation of cytoplasmic components. Basal autophagy in kidney cells is essential for the maintenance of kidney homeostasis, structure and function. Under stress conditions, autophagy is altered as part of the adaptive response of kidney cells, in a process that is tightly regulated by signalling pathways that can modulate the cellular autophagic flux - mammalian target of rapamycin, AMP-activated protein kinase and sirtuins are key regulators of autophagy. Dysregulated autophagy contributes to the pathogenesis of acute kidney injury, to incomplete kidney repair after acute kidney injury and to chronic kidney disease of varied aetiologies, including diabetic kidney disease, focal segmental glomerulosclerosis and polycystic kidney disease. Autophagy also has a role in kidney ageing. However, questions remain about whether autophagy has a protective or a pathological role in kidney fibrosis, and about the precise mechanisms and signalling pathways underlying the autophagy response in different types of kidney cells and across the spectrum of kidney diseases. Further research is needed to gain insights into the regulation of autophagy in the kidneys and to enable the discovery of pathway-specific and kidney-selective therapies for kidney diseases and anti-ageing strategies.
    DOI:  https://doi.org/10.1038/s41581-020-0309-2
  39. FASEB J. 2020 Jul 21.
    Xiong X, Rao G, Roy RV, Zhang Y, Means N, Dey A, Tsaliki M, Saha S, Bhattacharyya S, Dhar Dwivedi SK, Rao CV, McCormick DJ, Dhanasekaran D, Ding K, Gillies E, Zhang M, Yang D, Bhattacharya R, Mukherjee P.
      Macropinocytosis supports the metabolic requirement of RAS-transformed pancreatic ductal adenocarcinoma cells (PDACs). However, regulators of RAS-transformation (activation) that lead to macropinocytosis have not been identified. Herein, we report that UBAP2 (ubiquitin-binding associated protein 2), regulates the activation of KRAS and macropinocytosis in pancreatic cancer. We demonstrate that UBAP2 is highly expressed in both pancreatic cancer cell lines and tumor tissues of PDAC patients. The expression of UBAP2 is associated with poor overall survival in several cancers, including PDAC. Silencing UBAP2 decreases the levels of activated KRAS, and inhibits macropinocytosis, and tumor growth in vivo. Using a UBAP2-deletion construct, we demonstrate that the UBA-domain of UBAP2 is critical for the regulation of macropinocytosis and maintaining the levels of activated KRAS. In addition, UBAP2 regulates RAS downstream signaling and helps maintain RAS in the GTP-bound form. However, the exact mechanism by which UBAP2 regulates KRAS activation is unknown and needs further investigation. Thus, UBAP2 may be exploited as a potential therapeutic target to inhibit macropinocytosis and tumor growth in activated KRAS-driven cancers.
    Keywords:  KRAS; UBAP2; macropinocytosis; pancreatic cancer; small GTPases; therapeutic target
    DOI:  https://doi.org/10.1096/fj.201902826RR
  40. Nat Commun. 2020 Jul 21. 11(1): 3652
    Leier HC, Weinstein JB, Kyle JE, Lee JY, Bramer LM, Stratton KG, Kempthorne D, Navratil AR, Tafesse EG, Hornemann T, Messer WB, Dennis EA, Metz TO, Barklis E, Tafesse FG.
      Zika virus (ZIKV), an arbovirus of global concern, remodels intracellular membranes to form replication sites. How ZIKV dysregulates lipid networks to allow this, and consequences for disease, is poorly understood. Here, we perform comprehensive lipidomics to create a lipid network map during ZIKV infection. We find that ZIKV significantly alters host lipid composition, with the most striking changes seen within subclasses of sphingolipids. Ectopic expression of ZIKV NS4B protein results in similar changes, demonstrating a role for NS4B in modulating sphingolipid pathways. Disruption of sphingolipid biosynthesis in various cell types, including human neural progenitor cells, blocks ZIKV infection. Additionally, the sphingolipid ceramide redistributes to ZIKV replication sites, and increasing ceramide levels by multiple pathways sensitizes cells to ZIKV infection. Thus, we identify a sphingolipid metabolic network with a critical role in ZIKV replication and show that ceramide flux is a key mediator of ZIKV infection.
    DOI:  https://doi.org/10.1038/s41467-020-17433-9
  41. Nat Commun. 2020 Jul 20. 11(1): 3651
    Schleich K, Kase J, Dörr JR, Trescher S, Bhattacharya A, Yu Y, Wailes EM, Fan DNY, Lohneis P, Milanovic M, Lau A, Lenze D, Hummel M, Chapuy B, Leser U, Reimann M, Lee S, Schmitt CA.
      Lesion-based targeting strategies underlie cancer precision medicine. However, biological principles - such as cellular senescence - remain difficult to implement in molecularly informed treatment decisions. Functional analyses in syngeneic mouse models and cross-species validation in patient datasets might uncover clinically relevant genetics of biological response programs. Here, we show that chemotherapy-exposed primary Eµ-myc transgenic lymphomas - with and without defined genetic lesions - recapitulate molecular signatures of patients with diffuse large B-cell lymphoma (DLBCL). Importantly, we interrogate the murine lymphoma capacity to senesce and its epigenetic control via the histone H3 lysine 9 (H3K9)-methyltransferase Suv(ar)39h1 and H3K9me3-active demethylases by loss- and gain-of-function genetics, and an unbiased clinical trial-like approach. A mouse-derived senescence-indicating gene signature, termed "SUVARness", as well as high-level H3K9me3 lymphoma expression, predict favorable DLBCL patient outcome. Our data support the use of functional genetics in transgenic mouse models to incorporate basic biology knowledge into cancer precision medicine in the clinic.
    DOI:  https://doi.org/10.1038/s41467-020-17467-z
  42. Nat Rev Clin Oncol. 2020 Jul 24.
    Derynck R, Turley SJ, Akhurst RJ.
      TGFβ signalling has key roles in cancer progression: most carcinoma cells have inactivated their epithelial antiproliferative response and benefit from increased TGFβ expression and autocrine TGFβ signalling through effects on gene expression, release of immunosuppressive cytokines and epithelial plasticity. As a result, TGFβ enables cancer cell invasion and dissemination, stem cell properties and therapeutic resistance. TGFβ released by cancer cells, stromal fibroblasts and other cells in the tumour microenvironment further promotes cancer progression by shaping the architecture of the tumour and by suppressing the antitumour activities of immune cells, thus generating an immunosuppressive environment that prevents or attenuates the efficacy of anticancer immunotherapies. The repression of TGFβ signalling is therefore considered a prerequisite and major avenue to enhance the efficacy of current and forthcoming immunotherapies, including in tumours comprising cancer cells that are not TGFβ responsive. Herein, we introduce the mechanisms underlying TGFβ signalling in tumours and their microenvironment and discuss approaches to inhibit these signalling mechanisms as well as the use of these approaches in cancer immunotherapies and their potential adverse effects.
    DOI:  https://doi.org/10.1038/s41571-020-0403-1
  43. Nat Commun. 2020 Jul 24. 11(1): 3699
    Yang X, Yang Z, Wu Z, He Y, Shan C, Chai P, Ma C, Tian M, Teng J, Jin D, Yan W, Das P, Qu J, Xi P.
      Mitochondria play a critical role in generating energy to support the entire lifecycle of biological cells, yet it is still unclear how their morphological structures evolve to regulate their functionality. Conventional fluorescence microscopy can only provide ~300 nm resolution, which is insufficient to visualize mitochondrial cristae. Here, we developed an enhanced squaraine variant dye (MitoESq-635) to study the dynamic structures of mitochondrial cristae in live cells with a superresolution technique. The low saturation intensity and high photostability of MitoESq-635 make it ideal for long-term, high-resolution (stimulated emission depletion) STED nanoscopy. We performed time-lapse imaging of the mitochondrial inner membrane over 50 min (3.9 s per frame, with 71.5 s dark recovery) in living HeLa cells with a resolution of 35.2 nm. The forms of the cristae during mitochondrial fusion and fission can be clearly observed. Our study demonstrates the emerging capability of optical STED nanoscopy to investigate intracellular physiological processes with nanoscale resolution for an extended period of time.
    DOI:  https://doi.org/10.1038/s41467-020-17546-1
  44. Nat Chem Biol. 2020 Jul 20.
    Ruprecht B, Di Bernardo J, Wang Z, Mo X, Ursu O, Christopher M, Fernandez RB, Zheng L, Dill BD, Wang H, Xu Y, Liaw A, Mortison JD, Siriwardana N, Andresen B, Glick M, Tata JR, Kutilek V, Cornella-Taracido I, Chi A.
      Mass spectrometry-based discovery proteomics is an essential tool for the proximal readout of cellular drug action. Here, we apply a robust proteomic workflow to rapidly profile the proteomes of five lung cancer cell lines in response to more than 50 drugs. Integration of millions of quantitative protein-drug associations substantially improved the mechanism of action (MoA) deconvolution of single compounds. For example, MoA specificity increased after removal of proteins that frequently responded to drugs and the aggregation of proteome changes across cell lines resolved compound effects on proteostasis. We leveraged these findings to demonstrate efficient target identification of chemical protein degraders. Aggregating drug response across cell lines also revealed that one-quarter of compounds modulated the abundance of one of their known protein targets. Finally, the proteomic data led us to discover that inhibition of mitochondrial function is an off-target mechanism of the MAP2K1/2 inhibitor PD184352 and that the ALK inhibitor ceritinib modulates autophagy.
    DOI:  https://doi.org/10.1038/s41589-020-0572-3
  45. Cancer Res. 2020 Jul 21. pii: canres.0754.2020. [Epub ahead of print]
    Xiao Y, Clima R, Busch J, Rabien A, Kilic E, Villegas SL, Timmermann B, Attimonelli M, Jung K, Meierhofer D.
      Chromophobe renal cell carcinoma (chRCC) and renal oncocytoma (RO) are closely related, rare kidney tumors. Mutations in complex I (CI)-encoding genes play an important role in dysfunction of the oxidative phosphorylation (OXPHOS) system in RO but are less frequently observed in chRCC. As such, the relevance of OXPHOS status and role of CI mutations in chRCC remain unknown. To address this issue, we performed proteome and metabolome profiling as well as mitochondrial whole-exome sequencing to detect mitochondrial alterations in chRCC tissue specimens. Multi-omic analysis revealed downregulation of electron transport chain (ETC) components in chRCC that differed from the expression profile in RO. A decrease in mitochondrial (mt)DNA content, rather than CI mutations, was the main cause for reduced OXPHOS in chRCC. There was a negative correlation between protein and transcript levels of nuclear DNA- but not mtDNA-encoded ETC complex subunits in chRCC. In addition, the reactive oxygen species scavenger glutathione (GSH) was upregulated in chRCC due to decreased expression of proteins involved in GSH degradation. These results demonstrate that distinct mechanisms of OXPHOS exist in chRCC and RO and that expression levels of ETC complex subunits can serve as a diagnostic marker for this rare malignancy.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-0754
  46. Cell. 2020 Jul 23. pii: S0092-8674(20)30816-3. [Epub ahead of print]182(2): 270-296
    Oliver G, Kipnis J, Randolph GJ, Harvey NL.
      Mammals have two specialized vascular circulatory systems: the blood vasculature and the lymphatic vasculature. The lymphatic vasculature is a unidirectional conduit that returns filtered interstitial arterial fluid and tissue metabolites to the blood circulation. It also plays major roles in immune cell trafficking and lipid absorption. As we discuss in this review, the molecular characterization of lymphatic vascular development and our understanding of this vasculature's role in pathophysiological conditions has greatly improved in recent years, changing conventional views about the roles of the lymphatic vasculature in health and disease. Morphological or functional defects in the lymphatic vasculature have now been uncovered in several pathological conditions. We propose that subtle asymptomatic alterations in lymphatic vascular function could underlie the variability seen in the body's response to a wide range of human diseases.
    Keywords:  Alzheimer's; Crohn's disease; Lymphatics; Parkinson's; cardiovascular; glaucoma; immunity; inflammation; lymphatic function; lymphatic vasculature; lymphedema; myocardial infarction; neurological disease; obesity; tumors
    DOI:  https://doi.org/10.1016/j.cell.2020.06.039
  47. Nat Metab. 2020 Jul;2(7): 620-634
    Reilly SM, Hung CW, Ahmadian M, Zhao P, Keinan O, Gomez AV, DeLuca JH, Dadpey B, Lu D, Zaid J, Poirier B, Peng X, Yu RT, Downes M, Liddle C, Evans RM, Murphy AN, Saltiel AR.
      Catecholamines stimulate the mobilization of stored triglycerides in adipocytes to provide fatty acids (FAs) for other tissues. However, a large proportion is taken back up and either oxidized or re-esterified. What controls the disposition of these FAs in adipocytes remains unknown. Here, we report that catecholamines redirect FAs for oxidation through the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Adipocyte STAT3 is phosphorylated upon activation of β-adrenergic receptors, and in turn suppresses FA re-esterification to promote FA oxidation. Adipocyte-specific Stat3 KO mice exhibit normal rates of lipolysis, but exhibit defective lipolysis-driven oxidative metabolism, resulting in reduced energy expenditure and increased adiposity when they are on a high-fat diet. This previously unappreciated, non-genomic role of STAT3 explains how sympathetic activation can increase both lipolysis and FA oxidation in adipocytes, revealing a new regulatory axis in metabolism.
    DOI:  https://doi.org/10.1038/s42255-020-0217-6
  48. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30543-8. [Epub ahead of print]54(2): 282-292
    Tarazona OA, Pourquié O.
      The connection between cell fate transitions and metabolic shifts is gaining momentum in the study of cell differentiation in embryonic development, adult stem cells, and cancer pathogenesis. Here, we explore how metabolic transitions influence post-translational modifications (PTMs), which play central roles in the activation of transcriptional programs. PTMs can control the function of transcription factors acting as master regulators of cell fate as well as activation or repression of cell identity genes by regulating chromatin state via histone tail modifications. It now becomes clear that cell metabolism is an integral part of the complex landscape of regulatory mechanisms underlying cell differentiation.
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.035
  49. J Biochem. 2020 Jul 23. pii: mvaa085. [Epub ahead of print]
    Kofuji S, Sasaki AT.
      Growing cells increase multiple biosynthetic processes in response to the high metabolic demands needed to sustain proliferation. The even higher metabolic requirements in the setting of cancer provoke proportionately greater biosynthesis. Underappreciated key aspects of this increased metabolic demand are guanine nucleotides and adaptive mechanisms to regulate their concentration. Using the malignant brain tumor, glioblastoma, as a model, we have demonstrated that one of the rate-limiting enzymes for guanosine triphosphate (GTP) synthesis, inosine monophosphate dehydrogenase-2 (IMPDH2), is increased and IMPDH2 expression is necessary for the activation of de novo GTP biosynthesis. Moreover, increased IMPDH2 enhances RNA polymerase I and III transcription directly linking GTP metabolism to both anabolic capacity as well as nucleolar enlargement historically observed as associated with cancer. In this review, we will review in detail the basis of these new discoveries and, more generally, summarize the current knowledge on the role of GTP metabolism in cancer.
    Keywords:  GTP; IMPDH; glioblastoma; nucleolus; ribosome
    DOI:  https://doi.org/10.1093/jb/mvaa085
  50. Nat Rev Drug Discov. 2020 Jul 24.
    Cunnane SC, Trushina E, Morland C, Prigione A, Casadesus G, Andrews ZB, Beal MF, Bergersen LH, Brinton RD, de la Monte S, Eckert A, Harvey J, Jeggo R, Jhamandas JH, Kann O, la Cour CM, Martin WF, Mithieux G, Moreira PI, Murphy MP, Nave KA, Nuriel T, Oliet SHR, Saudou F, Mattson MP, Swerdlow RH, Millan MJ.
      The brain requires a continuous supply of energy in the form of ATP, most of which is produced from glucose by oxidative phosphorylation in mitochondria, complemented by aerobic glycolysis in the cytoplasm. When glucose levels are limited, ketone bodies generated in the liver and lactate derived from exercising skeletal muscle can also become important energy substrates for the brain. In neurodegenerative disorders of ageing, brain glucose metabolism deteriorates in a progressive, region-specific and disease-specific manner - a problem that is best characterized in Alzheimer disease, where it begins presymptomatically. This Review discusses the status and prospects of therapeutic strategies for countering neurodegenerative disorders of ageing by improving, preserving or rescuing brain energetics. The approaches described include restoring oxidative phosphorylation and glycolysis, increasing insulin sensitivity, correcting mitochondrial dysfunction, ketone-based interventions, acting via hormones that modulate cerebral energetics, RNA therapeutics and complementary multimodal lifestyle changes.
    DOI:  https://doi.org/10.1038/s41573-020-0072-x
  51. Nat Chem. 2020 Jul 20.
    Di Antonio M, Ponjavic A, Radzevičius A, Ranasinghe RT, Catalano M, Zhang X, Shen J, Needham LM, Lee SF, Klenerman D, Balasubramanian S.
      Substantial evidence now exists to support that formation of DNA G-quadruplexes (G4s) is coupled to altered gene expression. However, approaches that allow us to probe G4s in living cells without perturbing their folding dynamics are required to understand their biological roles in greater detail. Herein, we report a G4-specific fluorescent probe (SiR-PyPDS) that enables single-molecule and real-time detection of individual G4 structures in living cells. Live-cell single-molecule fluorescence imaging of G4s was carried out under conditions that use low concentrations of SiR-PyPDS (20 nM) to provide informative measurements representative of the population of G4s in living cells, without globally perturbing G4 formation and dynamics. Single-molecule fluorescence imaging and time-dependent chemical trapping of unfolded G4s in living cells reveal that G4s fluctuate between folded and unfolded states. We also demonstrate that G4 formation in live cells is cell-cycle-dependent and disrupted by chemical inhibition of transcription and replication. Our observations provide robust evidence in support of dynamic G4 formation in living cells.
    DOI:  https://doi.org/10.1038/s41557-020-0506-4
  52. Cancer Metab. 2020 ;8 17
    Eldad S, Hertz R, Vainer G, Saada A, Bar-Tana J.
      Background: ErbB2 breast cancer still remains an unmet need due to primary and/or acquired resistance to current treatment strategies. MEDICA compounds consist of synthetic long-chain α,ω-dicarboxylic acids previously reported to suppress breast cancer in PyMT transgenic mice.Methods: MEDICA efficacy and mode of action in the ErbB2 context was studied in ErbB2 transgenic mice and human breast cancer cells.
    Results: MEDICA treatment is shown here to suppress ErbB2 breast tumors and lung metastasis in ErbB2/neu MMTV transgenic mice, to suppress ErbB2/neu xenografts in nod/scid mice, and to suppress survival of AU565 and BT474 human ErbB2 breast cancer cells. Suppression of ErbB2 breast tumors by MEDICA is due to lipid raft disruption with loss of ErbB family members, including EGFR, ErbB2, and ErbB3. In addition, MEDICA inhibits mTORC1 activity, independently of abrogating the ErbB receptors and their signaling cascades. The double hit of MEDICA in abrogating ErbB and mTORC1 is partly accounted for by targeting mitochondria complex I.
    Conclusions: Mitochondrial targeting by MEDICA suppresses ErbB2 breast tumors and metastasis due to lipid raft disruption and inhibition of mTORC1 activity. Inhibition of mTORC1 activity by MEDICA avoids the resistance acquired by canonical mTORC1 inhibitors like rapalogs or mTOR kinase inhibitors.
    Keywords:  Breast cancer; ErbB2; Lipid rafts; Mitochondria; mTORC1
    DOI:  https://doi.org/10.1186/s40170-020-00223-8
  53. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30505-0. [Epub ahead of print]54(2): 212-225
    Bohnert M.
      Membrane contact sites (CSs) are specialized cellular regions where distinct organelles are actively positioned very close to each other, at a distance of just a few nanometers. Structurally, CS formation depends on tether proteins that physically link organellar membranes to each other. Functionally, these structures act as hotspots for communication and material transfer. In recent years, we are starting to understand that the cellular CS landscape is not static but instead responds dynamically to diverse metabolic cues. This review describes the interplay between cellular metabolism and CS-based organelle communication and discusses molecular mechanisms of contact modulation in cellular adaptation to changing metabolic requirements.
    Keywords:  CERT; ERMES; NVJ; OSBP; TMEM24/C2CD2L; extended synaptotagmin; vCLAMP
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.026
  54. Nutr Res. 2020 Jun 11. pii: S0271-5317(20)30471-1. [Epub ahead of print]80 66-77
    Komanetsky SM, Hedrick V, Sobreira T, Aryal UK, Kim SQ, Kim KH.
      Obesity is often accompanied by metabolic changes in adipocytes that are closely associated with metabolic disease. Although high sugar consumption contributes to obesity, it may also directly affect adipocytes by increasing the rate of glycolysis and formation of the glycolytic by-product methylglyoxal (MG). MG is a reactive dicarbonyl that irreversibly damages proteins and other cellular components. Although the accumulation of MG is clinically associated with hyperglycemia and diabetic complications, a better understanding of how proteins are regulated by MG is needed to evaluate its role in the pathogenesis of metabolic disease. Because adipocytes rely heavily on glycolysis for glucose disposal, we hypothesized that prolonged MG treatment at nontoxic concentrations would impact the landscape of proteins involved in glucose metabolism. To test this hypothesis, we treated 3T3-L1 adipocytes with MG (100 μmol/L) and used comparative proteomics to assess the effects. We identified 25 differentially expressed proteins in adipocytes treated with MG compared to the control. Our results suggested that MG induced metabolic changes typically associated with aerobic glycolysis, including a lowered expression of proteins involved in oxidative metabolism and increased expression of the glycolytic enzymes L-lactate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase. The detection of increased lactate secreted into the culture media of adipocytes treated with MG further supported these findings, as did gene expression analysis. In summary, these results indicate MG as a metabolic contributor to aerobic glycolysis in adipocytes, a potential adaptive response to increased glucose flux which over time could lead to permanent metabolic changes.
    Keywords:  Adipocytes; Aerobic glycolysis; Fumarate hydratase; Lactate dehydrogenase; Methylglyoxal; Proteomics
    DOI:  https://doi.org/10.1016/j.nutres.2020.06.009
  55. Cell Rep. 2020 Jul 21. pii: S2211-1247(20)30918-9. [Epub ahead of print]32(3): 107937
    Bruens L, Ellenbroek SIJ, Suijkerbuijk SJE, Azkanaz M, Hale AJ, Toonen P, Flanagan DJ, Sansom OJ, Snippert HJ, van Rheenen J.
      Calorie restriction (CR) extends lifespan through several intracellular mechanisms, including increased DNA repair, leading to fewer DNA mutations that cause age-related pathologies. However, it remains unknown how CR acts on mutation retention at the tissue level. Here, we use Cre-mediated DNA recombination of the confetti reporter as proxy for neutral mutations and follow these mutations by intravital microscopy to identify how CR affects retention of mutations in the intestine. We find that CR leads to increased numbers of functional Lgr5+ stem cells that compete for niche occupancy, resulting in slower but stronger stem cell competition. Consequently, stem cells carrying neutral or Apc mutations encounter more wild-type competitors, thus increasing the chance that they get displaced from the niche to get lost over time. Thus, our data show that CR not only affects the acquisition of mutations but also leads to lower retention of mutations in the intestine.
    Keywords:  Lgr5; calorie restriction; competition; diet; intestine; mutation retention; stem cells
    DOI:  https://doi.org/10.1016/j.celrep.2020.107937
  56. Nat Commun. 2020 Jul 22. 11(1): 3669
    Li Y, Li B, Li W, Wang Y, Akgül S, Treisman DM, Heist KA, Pierce BR, Hoff B, Ho CY, Ferguson DO, Rehemtulla A, Zheng S, Ross BD, Li JZ, Zhu Y.
      Recent characterization of spatiotemporal genomic architecture of IDH-wild-type multifocal glioblastomas (M-GBMs) suggests a clinically unobserved common-ancestor (CA) with a less aggressive phenotype, generating highly genetically divergent malignant gliomas/GBMs in distant brain regions. Using serial MRI/3D-reconstruction, whole-genome sequencing and spectral karyotyping-based single-cell phylogenetic tree building, we show two distinct types of tumor evolution in p53-mutant driven mouse models. Malignant gliomas/GBMs grow as a single mass (Type 1) and multifocal masses (Type 2), respectively, despite both exhibiting loss of Pten/chromosome 19 (chr19) and PI3K/Akt activation with sub-tetraploid/4N genomes. Analysis of early biopsied and multi-segment tumor tissues reveals no evidence of less proliferative diploid/2N lesions in Type 1 tumors. Strikingly, CA-derived relatively quiescent tumor precursors with ancestral diploid/2N genomes and normal Pten/chr19 are observed in the subventricular zone (SVZ), but are distantly segregated from multi focal Type 2 tumors. Importantly, PI3K/Akt inhibition by Rictor/mTORC2 deletion blocks distant dispersal, restricting glioma growth in the SVZ.
    DOI:  https://doi.org/10.1038/s41467-020-17382-3
  57. Nat Rev Clin Oncol. 2020 Jul 22.
    Gatenby RA, Brown JS.
      Many effective drugs for metastatic and/or advanced-stage cancers have been developed over the past decade, although the evolution of resistance remains the major barrier to disease control or cure. In large, diverse populations such as the cells that compose metastatic cancers, the emergence of cells that are resistant or that can quickly develop resistance is virtually inevitable and most likely cannot be prevented. However, clinically significant resistance occurs only when the pre-existing resistant phenotypes are able to proliferate extensively, a process governed by eco-evolutionary dynamics. Attempts to disrupt the molecular mechanisms of resistance have generally been unsuccessful in clinical practice. In this Review, we focus on the Darwinian processes driving the eco-evolutionary dynamics of treatment-resistant cancer populations. We describe a variety of evolutionarily informed strategies designed to increase the probability of disease control or cure by anticipating and steering the evolutionary dynamics of acquired resistance.
    DOI:  https://doi.org/10.1038/s41571-020-0411-1
  58. Nat Rev Neurosci. 2020 Jul 21.
    Bray N.
      
    DOI:  https://doi.org/10.1038/s41583-020-0354-7
  59. Sci Adv. 2020 Jun;6(25): eabb2210
    Fassl A, Brain C, Abu-Remaileh M, Stukan I, Butter D, Stepien P, Feit AS, Bergholz J, Michowski W, Otto T, Sheng Q, Loo A, Michael W, Tiedt R, DeAngelis C, Schiff R, Jiang B, Jovanovic B, Nowak K, Ericsson M, Cameron M, Gray N, Dillon D, Zhao JJ, Sabatini DM, Jeselsohn R, Brown M, Polyak K, Sicinski P.
      Inhibitors of cyclin-dependent kinases CDK4 and CDK6 have been approved for treatment of hormone receptor-positive breast cancers. In contrast, triple-negative breast cancers (TNBCs) are resistant to CDK4/6 inhibition. Here, we demonstrate that a subset of TNBC critically requires CDK4/6 for proliferation, and yet, these TNBC are resistant to CDK4/6 inhibition due to sequestration of CDK4/6 inhibitors into tumor cell lysosomes. This sequestration is caused by enhanced lysosomal biogenesis and increased lysosomal numbers in TNBC cells. We developed new CDK4/6 inhibitor compounds that evade the lysosomal sequestration and are efficacious against resistant TNBC. We also show that coadministration of lysosomotropic or lysosome-destabilizing compounds (an antibiotic azithromycin, an antidepressant siramesine, an antimalaria compound chloroquine) renders resistant tumor cells sensitive to currently used CDK4/6 inhibitors. Lastly, coinhibition of CDK2 arrested proliferation of CDK4/6 inhibitor-resistant cells. These observations may extend the use of CDK4/6 inhibitors to TNBCs that are refractory to current anti-CDK4/6 therapies.
    DOI:  https://doi.org/10.1126/sciadv.abb2210
  60. Dev Cell. 2020 Jul 20. pii: S1534-5807(20)30504-9. [Epub ahead of print]54(2): 256-267
    Ibar C, Irvine KD.
      The Hippo-Yes-associated protein (YAP) signaling network plays a central role as an integrator of signals that control cellular proliferation and differentiation. The past several years have provided an increasing appreciation and understanding of the diverse mechanisms through which metabolites and metabolic signals influence Hippo-YAP signaling, and how Hippo-YAP signaling, in turn, controls genes that direct cellular and organismal metabolism. These connections enable Hippo-YAP signaling to coordinate organ growth and homeostasis with nutrition and metabolism. In this review, we discuss the current understanding of some of the many interconnections between Hippo-YAP signaling and metabolism and how they are affected in disease conditions.
    Keywords:  Hippo; Yap; metabolism
    DOI:  https://doi.org/10.1016/j.devcel.2020.06.025