I nsights into the molecular mechanisms of apoptosis induced by glucose deprivation Raffaella Iurlaro ADVERTIMENT . La consulta d’aquesta tesi queda condicionada a l’acceptació de les següents condicions d'ús: La difusió d’aquesta tesi per mitjà del servei TDX ( www.tdx.cat ) i a través del Dipòsit Digital de la UB ( diposit.ub.edu ) ha estat autoritzada pels titulars dels drets de propietat intel·lectual únicament per a usos privats emmarcats en activitats d’investigació i docència. No s’autoritza la seva reproducció amb finalitats de lucre ni la seva difusió i posada a disposici ó des d’un lloc aliè al servei TDX ni al Dipòsit Digital de la UB . No s’autoritza la presentació del seu contingut en una finestra o marc aliè a TDX o al Dipòsit Digital de la UB (framing). Aquesta reserva de drets afecta tant al resum de presentació de la tesi com als seus continguts. En la utilització o cita de parts de la tesi és obligat indicar el nom de la persona autora. ADVERTENCIA . 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This chapter was originally published in the book Conceptual Background and Bioenergetic/Mitochondrial Aspects Of Oncometabolism, Vol.542, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who know you, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: http://www.elsevier.com/locate/permissionusematerial From: Raffaella Iurlaro, Clara Lucía León-Annicchiarico, Cristina Muñoz-Pinedo, Regulation of Cancer Metabolism by Oncogenes and Tumor Suppressors. In Lorenzo Galluzzi, Guido Kroemer editors: Methods In Enzymology, Vol. 542, Burlington: Academic Press, 2014, pp.59-80. ISBN: 978-0-12-416618-9 © Copyright 2014 Elsevier Inc. Academic Press Elsevier Author's personal copy CHAPTER THREE Regulation of Cancer Metabolism by Oncogenes and Tumor Suppressors Raffaella Iurlaro1, Clara Lucía León-Annicchiarico1, Cristina Muñoz-Pinedo2 Cell Death Regulation Group, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain 1These authors contributed equally. 2Corresponding author: e-mail address: [email protected] Contents 1. Introduction 60 2. HIF-1: Regulator of Hypoxic Responses and Cancer Metabolism 61 3. The PI3K–AKT–PTEN Pathway Regulates Metabolism 62 4. mTOR Controls Anabolism and It Is Inhibited By AMPK Upon Metabolic Stress 64 5. c-Myc Promotes Aerobic Anabolism 66 6. Ras Stimulates Glycolysis and the PPP 68 7. NF-kappaB Regulates Inflammation and Proliferation But Also Metabolism 69 8. Retinoblastoma: Suppressing Tumorogenesis and Anabolism 70 9. p53 Regulates Multiple Metabolic Pathways 71 10. Conclusions 74 Acknowledgments 74 References 74 Abstract Cell proliferation requires the coordination of multiple signaling pathways as well as the provision of metabolic substrates. Nutrients are required to generate such building blocks and their form of utilization differs to significant extents between malignant tis- sues and their nontransformed counterparts. Thus, oncogenes and tumor suppressor genes regulate the proliferation of cancer cells also by controlling their metabolism. Here, we discuss the central anabolic functions of the signaling pathways emanating from mammalian target of rapamycin, MYC, and hypoxia-inducible factor-1. Moreover, we analyze how oncogenic proteins like phosphoinositide-3-kinase, AKT, and RAS, tumor suppressors such as phosphatase and tensin homolog, retinoblastoma, and p53, as well as other factors associated with the proliferation or survival of cancer cells, such as NF-kB, regulate cellular metabolism. # Methods in Enzymology, Volume 542 2014 Elsevier Inc. 59 ISSN 0076-6879 All rights reserved. http://dx.doi.org/10.1016/B978-0-12-416618-9.00003-0 Author's personal copy 60 Raffaella Iurlaro et al. ABBREVIATIONS AMPK AMP-activated protein kinase COX cytochrome c oxidase GLS1 glutaminase 1 HIF-1 hypoxia-inducible factor 1 IĸB inhibitor of ĸB proteins LDH lactate dehydrogenase LKB1 liver kinase B1 mTOR mammalian (or mechanistic) target of rapamycin PDH pyruvate dehydrogenase PDK1 pyruvate dehydrogenase kinase 1 PHD prolyl-4-hydroxylase domain protein pRb retinoblastoma protein PtdIns(3,4,5) P3 phosphatidylinositol-3,4,5-trisphosphate PTEN phosphatase and tensin homologue SCO2 synthesis of cytochrome c oxidase 2 SREBP sterol regulatory element-binding protein TIGAR TP53 (tumor protein 53)-induced glycolysis and apoptosis regulator TSC1/2 tuberous sclerosis 1/2 VHL von Hippel–Lindau 1. INTRODUCTION Most oncogenes and tumor suppressor genes encode proteins that promote cellular proliferation or cell cycle arrest. In recent years, we are learning that proliferation is tightly coupled with metabolic changes. For this reason, cancer metabolism is an area of intense research, since the metabolism of cancer cells can be exploited for therapeutic purposes (Munoz-Pinedo, El Mjiyad, & Ricci, 2012). In accordance to the normal function of their encoded proteins, oncogenes or tumor suppressors regulate cellular metabolism (Vander Heiden, Cantley, & Thompson, 2009). This is an intrinsic part of their program to reduce or promote cell proliferation. Oncogenes promote glucose and amino acid uptake and metabolism in order to make new lipids, nucleotides, and proteins. Conversely, tumor suppressors upregulate mitochondrial respiration and Krebs (TCA) cycle (see review by Frezza and colleagues, Chapter 1 of this volume). We will discuss how several oncogenes and tumor suppressors regulate cellular metabolism. Author's personal copy Regulation of Cancer Metabolism by Oncogenes 61 2. HIF-1: REGULATOR OF HYPOXIC RESPONSES AND CANCER METABOLISM Highly proliferating tumor cells are characterized by a hypoxic micro- environment due to the increased oxygen consumption, which stimulates metabolic reprogramming (Vaupel, Thews, & Hoeckel, 2001). The master regulator of cellular responses to low oxygen is hypoxia-inducible factor 1 (HIF-1), a transcription factor induced by hypoxic conditions and whose levels are increased in many human cancers even under normoxia (Semenza, 2010). Under normal oxygen conditions, HIF-1 is degraded by the proteasome after prolyl hydroxylation by prolyl-4-hydroxylase domain proteins (PHDs) and ubiquitination by the tumor suppressor von Hippel–Lindau (VHL) (Kaelin & Ratcliffe, 2008; Fig. 3.1). HIF-1 can also be constitutively activated by genetic alterations, such as the loss of function of VHL in renal cancer cells, or due to the accumulation of metabolites such as fumarate or succinate (Boulahbel, Duran, & Gottlieb, 2009). Cancer cells frequently undergo oxygen shortage which inhibits the prolyl hydroxylases and stabilizes HIF-1, which induces the expression of hundreds of genes involved in angiogenesis, metabolism, apoptosis, and proliferation. The major metabolic effect of HIF-1 is to trigger the switch from mito- chondrial oxidative phosphorylation (OXPHOS) to anaerobic glycolysis. HIF-1 induces the expression of glucose transporters (GLUT-1, GLUT-3) toenhanceglucoseuptakeanditupregulatesglycolyticenzymesandthelactate dehydrogenaseA(LDHA)subunittostimulatetheconversionofpyruvateinto lactate (Brahimi-Horn, Chiche, & Pouyssegur, 2007; Semenza, 2011; Fig. 3.1). Importantly, HIF-1 activates the pyruvate dehydrogenase kinase 1 (PDK1; Kim, Tchernyshyov, Semenza,