Littérature scientifique sur le sujet « BPGM, cancer cells metabolism, Warburg effect, Reverse Warburg effect »

Autophagy is a highly regulated-cell pathway for degrading long-lived proteins as well as for clearing cytoplasmic organelles. Autophagy is a key contributor to cellular homeostasis and metabolism. Warburg hypothesized that cancer growth is frequently associated with a deviation of a set of energy generation mechanisms to a nonoxidative breakdown of glucose. This cellular phenomenon seems to rely on a respiratory impairment, linked to mitochondrial dysfunction. This mitochondrial dysfunction results in a switch to anaerobic glycolysis. It has been recently suggested that epithelial cancer cells may induce the Warburg effect in neighboring stromal fibroblasts in which autophagy was activated. These series of observations drove to the proposal of a putative reverse Warburg effect of pathophysiological relevance for, at least, some tumor phenotypes. In this review we introduce the autophagy process and its regulation and its selective pathways and role in cancer cell metabolism. We define and describe the Warburg effect and the newly suggested “reverse” hypothesis. We also discuss the potential value of modulating autophagy with several pharmacological agents able to modify the Warburg effect. The association of the Warburg effect in cancer and stromal cells to tumor-related autophagy may be of relevance for further development of experimental therapeutics as well as for cancer prevention.

Two basic types of cancers were identified – those with the mitochondrial dysfunction in cancer cells (the Warburg effect) or in fibroblasts supplying energy rich metabolites to a cancer cell with functional mitochondria (the reverse Warburg effect). Inner membrane potential of the functional and dysfunctional mitochondria measured by fluorescent dyes (e.g. by Rhodamine 123) displays low and high values (apparent potential), respectively, which is in contrast to the level of oxidative metabolism. Mitochondrial dysfunction (full function) results in reduced (high) oxidative metabolism, low (high) real membrane potential, a simple layer (two layers) of transported protons around mitochondria, and high (low) damping of microtubule electric polar vibrations. Crucial modifications are caused by ordered water layer (exclusion zone). For the high oxidative metabolism one proton layer is at the mitochondrial membrane and the other at the outer rim of the ordered water layer. High and low damping of electric polar vibrations results in decreased and increased electromagnetic activity in cancer cells with the normal and the reverse Warburg effect, respectively. Due to nonlinear properties the electromagnetic frequency spectra of cancer cells and transformed fibroblasts are shifted in directions corresponding to their power deviations resulting in disturbances of interactions and escape from tissue control. The cancer cells and fibroblasts of the reverse Warburg effect tumors display frequency shifts in mutually opposite directions resulting in early generalization. High oxidative metabolism conditions high aggressiveness. Mitochondrial dysfunction, a gate to malignancy along the cancer transformation pathway, forms a narrow neck which could be convenient for cancer treatment.

Most tumors consume large amounts of glucose. Concepts to explain the mechanisms that mediate the achievement of this metabolic need have proposed a switch of the tumor mass to aerobic glycolysis. Depending on whether primarily tumor or stroma cells undergo such a commutation, the terms ‘Warburg effect’ or ‘reverse Warburg effect’ were coined to describe the underlying biological phenomena. However, current in vitro systems relying on 2-D culture, single cell-type spheroids, or basal-membrane extract (BME/Matrigel)-containing 3-D structures do not thoroughly reflect these processes. Here, we aimed to establish a BME/Matrigel-free 3-D microarray cancer model to recapitulate the metabolic interplay between cancer and stromal cells that allows mechanistic analyses and drug testing. Human HT-29 colon cancer and CCD-1137Sk fibroblast cells were used in mono- and co-cultures as 2-D monolayers, spheroids, and in a cell-chip format. Metabolic patterns were studied with immunofluorescence and confocal microscopy. In chip-based co-cultures, HT-29 cells showed facilitated 3-D growth and increased levels of hexokinase-2, TP53-induced glycolysis and apoptosis regulator (TIGAR), lactate dehydrogenase, and: translocase of outer mitochondrial membrane 20 (TOMM20), when compared with HT-29 mono-cultures. Fibroblasts co-cultured with HT-29 cells expressed higher levels of mono-carboxylate transporter 4, hexokinase-2, microtubule-associated proteins 1A/1B light chain 3, and ubiquitin-binding protein p62 than in fibroblast mono-cultures, in both 2-D cultures and chips. Tetramethylrhodamin-methylester (TMRM) live-cell imaging of chip co-cultures revealed a higher mitochondrial potential in cancer cells than in fibroblasts. The findings demonstrate a crosstalk between cancer cells and fibroblasts that affects cellular growth and metabolism. Chip-based 3-D co-cultures of cancer cells and fibroblasts mimicked features of the reverse Warburg effect.

Cancer cells alter metabolic processes to sustain their characteristic uncontrolled growth and proliferation. These metabolic alterations include (1) a shift from oxidative phosphorylation to aerobic glycolysis to support the increased need for ATP, (2) increased glutaminolysis for NADPH regeneration, (3) altered flux through the pentose phosphate pathway and the tricarboxylic acid cycle for macromolecule generation, (4) increased lipid uptake, lipogenesis, and cholesterol synthesis, (5) upregulation of one-carbon metabolism for the production of ATP, NADH/NADPH, nucleotides, and glutathione, (6) altered amino acid metabolism, (7) metabolism-based regulation of apoptosis, and (8) the utilization of alternative substrates, such as lactate and acetate. Altered metabolic flux in cancer is controlled by tumor-host cell interactions, key oncogenes, tumor suppressors, and other regulatory molecules, including non-coding RNAs. Changes to metabolic pathways in cancer are dynamic, exhibit plasticity, and are often dependent on the type of tumor and the tumor microenvironment, leading in a shift of thought from the Warburg Effect and the “reverse Warburg Effect” to metabolic plasticity. Understanding the complex nature of altered flux through these multiple pathways in cancer cells can support the development of new therapies.

Abstract Introduction: Altered cellular metabolism is a hallmark of every cancer cell. Aerobic glycolysis ("The Warburg Effect") is one of the earliest recognized metabolic abnormalities in cancer cells whereby extracellular glucose is preferentially metabolized and eventually processed to generate lactate and energy in the form of ATP before the former is released extracellularly, irrespective of oxygen availability. While extracellular lactate produced and released from cancer cells has traditionally been considered a waste metabolic by-product, recent understanding of cell metabolism suggests that it can also serve as a primary metabolic fuel for cancer cells via uptake by monocarboxylate transporters (MCTs). Our goal was to evaluate this "Reverse Warburg Effect" phenomenon in multiple myeloma (MM) cells and determine if it can be exploited for therapeutic purposes. Methods: All HMCLs, MM1S, RPMI-8226 and U266, were grown in RPMI-1640 cell culture medium containing 11 mM glucose and supplemented with 10% dialyzed fetal bovine serum (FBS) and 2 mM Glutamine. Primary MM cells were extracted using magnetic bead CD138 positive selection from MM patient bone marrow aspirates. For 13C-labeling experiments, HMCLs and primary MM cells were suspended in RPMI-1640 cell culture media containing 13C-labeled isotopes. Isotopomer analysis of glycolytic and tricarboxylic acid (TCA) cycle metabolites from HMCL and primary MM cell pellets was performed using Agilent Technologies 5975C gas chromatography-mass spectrometry. Small molecule inhibitors, AZD3965 and syrosingopine, were purchased from Selleck Chemicals and Sigma respectively. Cellular viability and proliferation were measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrasodium bromide (MTT) and CCK-8 assays respectively. MCT-1 and MCT-4 antibodies for western blotting were utilized to evaluate their cell membrane expression on HMCLs. Results: The HMCLs, MM1S and RPMI-8226 as well as primary CD138+ cells from MM patient bone marrow were cultured in cell culture media containing physiological levels (1 mM) of U-13C-Lactate. The incorporation of extracellular 13C into the intracellular glycolytic and TCA cycle metabolite pool was observed (Fig 1) based on the expected isotopomeric patterns, demonstrating the Reverse Warburg Effect in MM cells. The relative contribution of carbon substrate by extracellular lactate compared to extracellular glucose was assessed in the following HMCLs: MM1S, RPMI-8226 and U266 cells by culturing in cell culture media containing 3-13C-Lactate and U-13C-Glucose. Extracellular lactate (yellow bar) contribution to the formation of TCA metabolites equaled that of glucose (red bar) based on the expected isotopomer patterns, suggesting the relative importance of extracellular lactate as an essential nutrient like glucose (Fig 2). Since MCT-1 and MCT-4 are key bidirectional cell membrane transporters of lactate in and out of cells, we explored the clinical significance of their gene expression level on clinical outcomes using the COMMPASS dataset provided by the Multiple Myeloma Research Foundation (MMRF). When MM patients were dichotomized at above or below the median of the expression levels of fragments per kilobase of transcript per million (FPKM), MCT-1 and MCT-4 overexpression conferred a worse progression free survival and overall survival (Fig 3). The MCT-1/MCT-4 protein expression was detectable across the various HMCLs: MM1S, U266 and RPMI-8226 (Fig 4). Inhibition of MCT-1 by specific inhibitor AZD3965 was able to reduce proliferation but not affect viability of HMCLs at 48 hours (Fig 5). However, dual inhibition of MCT-1/MCT-4 using syrosingopine was able to significantly reduce proliferation and decrease viability of HMCLs in a dose dependent fashion (Fig 6). Finally, dual inhibition of MCT-1/MCT-4 using syrosingopine reduced the utilization of extracellular lactate into the TCA cycle pool by HMCLs in media containing 3-13C-Lactate (Fig 7). Conclusion: Utilization of extracellular lactate via Reverse Warburg Effect phenomenon appears highly active in MM cells. Disrupting the utilization of extracellular lactate by dual inhibition of both MCT-1 and MCT-4 appears therapeutic. In the future, dual inhibition of MCT-1/MCT-4 in combination with other anti-MM therapies should be evaluated to determine synergistic therapeutic potential. Figure 1 Figure 1. Disclosures Kumar: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Sanofi: Research Funding; Novartis: Research Funding; Antengene: Consultancy, Honoraria; Beigene: Consultancy; Bluebird Bio: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Roche-Genentech: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding.

Abstract It is well established that cancer cells acquire energy via the Warburg effect and oxidative phosphorylation. Citrate is considered to play a crucial role in cancer metabolism by virtue of its production in the reverse Krebs cycle from glutamine. Here, we review the evidence that extracellular citrate is one of the key metabolites of the metabolic pathways present in cancer cells. We review the different mechanisms by which pathways involved in keeping redox balance respond to the need of intracellular citrate synthesis under different extracellular metabolic conditions. In this context, we further discuss the hypothesis that extracellular citrate plays a role in switching between oxidative phosphorylation and the Warburg effect while citrate uptake enhances metastatic activities and therapy resistance. We also present the possibility that organs rich in citrate such as the liver, brain and bones might form a perfect niche for the secondary tumour growth and improve survival of colonising cancer cells. Consistently, metabolic support provided by cancer-associated and senescent cells is also discussed. Finally, we highlight evidence on the role of citrate on immune cells and its potential to modulate the biological functions of pro- and anti-tumour immune cells in the tumour microenvironment. Collectively, we review intriguing evidence supporting the potential role of extracellular citrate in the regulation of the overall cancer metabolism and metastatic activity.

Fibroblasts are important contributors to cancer development. They create a tumor microenvironment and modulate our metabolism and treatment resistance. In the present paper, we demonstrate that healthy fibroblasts induce metabolic coupling with non-small cell lung cancer cells by down-regulating the expression of glycolytic enzymes in cancer cells and increasing the fibroblasts’ ability to release lactate and thus support cancer cells with energy-rich glucose-derived metabolites, such as lactate and pyruvate—a process known as the reverse Warburg effect. We demonstrate that these changes result from a fibroblasts-stimulated increase in the expression of fructose bisphosphatase (Fbp) in cancer cells and the consequent modulation of Hif1α function. We show that, in contrast to current beliefs, in lung cancer cells, the predominant and strong interaction with the Hif1α form of Fbp is not the liver (Fbp1) but in the muscle (Fbp2) isoform. Since Fbp2 oligomerization state and thus, its role is regulated by AMP and NAD+—crucial indicators of cellular metabolic conditions—we hypothesize that the Hif1α-dependent regulation of the metabolism in cancer is modulated through Fbp2, a sensor of the energy and redox state of a cell.

e13509 Background: Glioblastoma (GB) is characterized by dysregulated metabolism, utilizing glycolysis for energy production to support unrestricted growth. BPM 31510, an ubidecarenone containing lipid nanodispersion effectuates a switch in cancer energy sourcing from glycolysis towards mitochondrial OXPHOS, i.e. reverses Warburg effect, providing rationale for its potential utility in treatment of GB. The current study investigated utility of BPM31510 alone and in combination with temozolomide. Methods: In vitro (U251-MG human GB cell line) and in vivo (C6 glioma rat model) preclinical models of GB were used to assess the anti-cancer activity of BPM 31510 alone (100 mg/kg/d) and combination with TMZ/bevacizumab (BEV). In addition, an in vitro model of acquired TMZ chemo-resistance was established by progressive adaptation of parental U251-MG cells to increasing doses of TMZ. Parental and resistant subclones (TMZ-R) were used to define activity of BPM31510 in the TMZ-refractory setting. Results: In vitro results demonstrated that BPM 31510 has anti-cancer activity in both parental and TMZ-R U251-MG cells with EC50 values of ~400 µM and 800 µM, respectively. Importantly, BPM 31510 treatment also resensitized TMZ-R cell lines to TMZ. In vivo, BPM 31510 treatment was associated with increasing duration of survival; one fifth of the rats treated achieved survival greater than 15 days post implantation, a response not observed in the control or irradiation arms of the study. Assessment of the combination of BPM 31510 with TMZ or BEV in the in vivoC6 glioma rat model is ongoing. A phase I open-label, non-randomized clinical trial to evaluate the safety and tolerability of BPM31510 in patients with recurrent BEV-refractory GB, as well as the changes in GB metabolism by SUV-PET imaging in response to treatment is under investigation. Conclusions: Preclinical data demonstrate that BPM 31510 has potential anti-cancer activity alone and in combination with standard therapy regimens and alleviates TMZ chemo-resistance in preclinical models of GB. These results provide support of a Phase 1 clinical study of BPM31510 in GB; this study is actively enrolling.

e18080 Background: Energy metabolism heterogeneity is a hallmark in ovarian cancer, namely the Warburg effect and the reverse Warburg effects coexist in ovarian cancer. Exploration of energy metabolism heterogeneity benefits for discovery of the effective biomarkers for ovarian cancers. Methods: Comprehensive analysis of mitochondrial proteomics data (1198 mitochondrial differentially expressed proteins), mitochondrial phosphorpoteomics data (67 mitochondrial phosphorproteins), proteomics data (205 differentially expressed proteins), and transcriptomics data (20115 genes in 419 ovarian cancer samples) was useful. Results: It revealed (i) the upregulations of rate-limiting enzymes PKM2 in glycolysis, IDH2 in Kreb’s cycle, and UQCRH in oxidative phosphorylation (OXPHOS) pathways, (ii) the upregulation of PDHB that converts pyruvate from glycolysis into acetyl-CoA in Kreb’s cycle. Anti-parasite drug ivermectin demonstrated its strong abilities to inhibit proliferation and cell cycle progression and promote apoptosis in EOC cells, through molecular networks to target PFKP in glycolysis, IDH2 and IDH3B in Kreb’s cycle, ND2, ND5, CYTB, and UQCRH in OXPHOS, and MCT1 and MCT4 in lactate shuttle to inhibit EOC growth. Those results were further confirmed in the ovarian cancer cell models and tissues. Conclusions: It clearly concluded that ivermectin might have new potential for ovarian cancer treatment through regulating energy metabolism pathways. These findings provide more accurate understanding of molecular mechanisms of ovarian cancers and discovery of effective energy-metabolism-heterogeneity-based therapeutic drugs for ovarian cancers.

This review presents a hypothesis to explain the role of melatonin in regulating glucose metabolism in cancer cells. Many cancer cells use cytosolic glycolysis (the Warburg effect) to produce energy (ATP). Under these conditions, glucose is primarily converted to lactate which is released into the blood in large quantities. The Warburg effect gives cancer cells advantages in terms of enhanced macromolecule synthesis required for accelerated cellular proliferation, reduced cellular apoptosis which enhances tumor biomass and a greater likelihood of metastasis. Based on available data, high circulating melatonin levels at night serve as a signal for breast cancer cells to switch from cytosolic glycolysis to mitochondrial glucose oxidation and oxidative phosphorylation for ATP production. In this situation, melatonin promotes the synthesis of acetyl-CoA from pyruvate; we speculate that melatonin does this by inhibiting the mitochondrial enzyme pyruvate dehydrogenase kinase (PDK) which normally inhibits pyruvate dehydrogenase complex (PDC), the enzyme that controls the pyruvate to acetyl-CoA conversion. Acetyl-CoA has several important functions in the mitochondria; it feeds into the citric acid cycle which improves oxidative phosphorylation and, additionally, it is a necessary co-factor for the rate limiting enzyme, arylalkylamine N-acetyltransferase, in mitochondrial melatonin synthesis. When breast cancer cells are using cytosolic glycolysis (during the day) they are of the cancer phenotype; at night when they are using mitochondria to produce ATP via oxidative phosphorylation, they have a normal cell phenotype. If this day:night difference in tumor cell metabolism is common in other cancers, it indicates that these tumor cells are only cancerous part of the time. We also speculate that high nighttime melatonin levels also reverse the insensitivity of tumors to chemotherapy.

Many kind of cancer cells exploit glycolysis rather than oxidative phosphorylation for energy production even in the presence of oxygen. This kind of metabolism, although less efficient in terms of ATP production, generates high levels of glycolytic intermediates necessary to support the high biosynthetic flux of rapidly proliferating cells. . This mechanism is further enhanced in cancer cells by the expression of a particular form of pyruvate kinase -M2 (PKM2) which promote a low efficiency glycolysis (in terms or ATP production) and consequently an increase in the formation of biosynthetic metabolites. In this work we investigate the role of Bisphosphogliceratemutase (BPGM) an enzyme involved in the metabolic reprogramming of highly proliferating cancer cells. BPGM acts both as a mutase, converting the glycolytic intermediate 1,3-bisphosphoglycerate to 2,3-bisphosphoglycerate and as a phosphatase, converting the 1,3-bisphosphoglycerate to 3-phosphoglycerate. BPGM is an erythrocyte-specific enzyme but our real time PCR and western blotting experiments show its expression in many cancer cell lines and in proliferating primary human fibroblasts. BPGM silencing lead to a strong decrease of cell proliferation rate BPGM activity in cancer cell lead to the skipping of the first ATP production in the glycolytic pathway of glycolysis, causing an increase of glycolytic flux necessary to sustain the high rate of intermediates production needed for support cancer cells growth.