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AMPK-regulated and Akt-dependent enhancement of glucose uptake is essential in ischemic preconditioning-alleviated reperfusion injury. PLoS One 2013; 8:e69910. [PMID: 23922853 PMCID: PMC3724784 DOI: 10.1371/journal.pone.0069910] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/13/2013] [Indexed: 01/04/2023] Open
Abstract
AIMS Ischemic preconditioning (IPC) is a potent form of endogenous protection. However, IPC-induced cardioprotective effect is significantly blunted in insulin resistance-related diseases and the underlying mechanism is unclear. This study aimed to determine the role of glucose metabolism in IPC-reduced reperfusion injury. METHODS Normal or streptozotocin (STZ)-treated diabetic rats subjected to 2 cycles of 5 min ischemia/5 min reperfusion prior to myocardial ischemia (30 min)/reperfusion (3 h). Myocardial glucose uptake was determined by (18)F-fluorodeoxyglucose-positron emission tomography (PET) scan and gamma-counter biodistribution assay. RESULTS IPC exerted significant cardioprotection and markedly improved myocardial glucose uptake 1 h after reperfusion (P<0.01) as evidenced by PET images and gamma-counter biodistribution assay in ischemia/reperfused rats. Meanwhile, myocardial translocation of glucose transporter 4 (GLUT4) to plasma membrane together with myocardial Akt and AMPK phosphorylation were significantly enhanced in preconditioned hearts. Intramyocardial injection of GLUT4 siRNA markedly decreased GLUT4 expression and blocked the cardioprotection of IPC as evidence by increased myocardial infarct size. Moreover, the PI3K inhibitor wortmannin significantly inhibited activation of Akt and AMPK, reduced GLUT4 translocation, glucose uptake and ultimately, depressed IPC-induced cardioprotection. Furthermore, IPC-afforded antiapoptotic effect was markedly blunted in STZ-treated diabetic rats. Exogenous insulin supplementation significantly improved glucose uptake via co-activation of myocardial AMPK and Akt and alleviated ischemia/reperfusion injury as evidenced by reduced myocardial apoptosis and infarction size in STZ-treated rats (P<0.05). CONCLUSIONS The present study firstly examined the role of myocardial glucose metabolism during reperfusion in IPC using direct genetic modulation in vivo. Augmented glucose uptake via co-activation of myocardial AMPK and Akt in reperfused myocardium is essential to IPC-alleviated reperfusion injury. This intrinsic metabolic modulation and cardioprotective capacity are present in STZ-treated hearts and can be triggered by insulin.
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Navrátilová J, Hankeová T, Beneš P, Šmarda J. Low-Glucose Conditions of Tumor Microenvironment Enhance Cytotoxicity of Tetrathiomolybdate to Neuroblastoma Cells. Nutr Cancer 2013; 65:702-10. [DOI: 10.1080/01635581.2013.789118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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53
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Akt1 is the principal Akt isoform regulating apoptosis in limiting cytokine concentrations. Cell Death Differ 2013; 20:1341-9. [PMID: 23787999 DOI: 10.1038/cdd.2013.63] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 04/29/2013] [Accepted: 05/14/2013] [Indexed: 11/08/2022] Open
Abstract
The activation of the Akt signalling in response to cytokine receptor signalling promotes protein synthesis, cellular growth and proliferation. To determine the role of Akt in interleukin-3 (IL-3) signalling, we generated IL-3-dependent myeloid cell lines from mice lacking Akt1, Akt2 or Akt3. Akt1 deletion resulted in accelerated apoptosis at low concentrations of IL-3. Expression of constitutively active Akt1 was sufficient to delay apoptosis in response to IL-3 withdrawal, but not sufficient to induce proliferation in the absence of IL-3. Akt1 prolonged survival of Bim- or Bad-deficient cells, but not cells lacking Puma, indicating that Akt1-dependent repression of apoptosis was in part dependent on Puma and independent of Bim or Bad. Our data show that a key role of Akt1 during IL-3 signalling is to repress p53-dependent apoptosis pathways, including transcriptional upregulation of Puma. Moreover, our data indicate that regulation of BH3-only proteins by Akt is dispensable for Akt-dependent cell survival.
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Müller A, Zang C, Chumduri C, Dörken B, Daniel PT, Scholz CW. Concurrent inhibition of PI3K and mTORC1/mTORC2 overcomes resistance to rapamycin induced apoptosis by down-regulation of Mcl-1 in mantle cell lymphoma. Int J Cancer 2013; 133:1813-24. [DOI: 10.1002/ijc.28206] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 03/21/2013] [Indexed: 11/12/2022]
Affiliation(s)
| | - Chuanbing Zang
- Department of Oncology and Hematology; University Medical Center Charité, Campus; Berlin-Mitte; Germany
| | | | - Bernd Dörken
- Department of Hematology; Oncology and Tumor Immunology; University Medical Center Charité, Campus Berlin-Buch, Humboldt University; Berlin; Germany
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Cho KS, Joo SH, Choi CS, Kim KC, Ko HM, Park JH, Kim P, Hur J, Lee SH, Bahn GH, Ryu JH, Lee J, Han SH, Kwon KJ, Shin CY. Glucose deprivation reversibly down-regulates tissue plasminogen activator via proteasomal degradation in rat primary astrocytes. Life Sci 2013; 92:929-37. [DOI: 10.1016/j.lfs.2013.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 03/12/2013] [Accepted: 03/20/2013] [Indexed: 11/30/2022]
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Chen YT, Feng B, Chen LB. Update of research on drug resistance in small cell lung cancer chemotherapy. Asian Pac J Cancer Prev 2013; 13:3577-81. [PMID: 23098422 DOI: 10.7314/apjcp.2012.13.8.3577] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small cell lung cancer (SCLC) is characterized by a short cell doubling time, rapid progression and early occurrence of blood-borne and lymph metastasis. The malignancy is the highest of all lung cancer types. Although SCLC has a relatively good initial response to chemotherapy as well as radiotherapy, relapse or disease progression may occur quickly after the initial treatment. Drug resistance, especially multi-drug resistance, is the most important cause of failure of SCLC chemotherapy. This article provides a brief update of research on mechanisms of drug resistance in SCLC and reversal strategies.
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Affiliation(s)
- Yi-Tian Chen
- Department of Medical Oncology, Jinling Hospital, Nanjing, China
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57
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The role of E3 ubiquitin ligase Cbl proteins in interleukin-2-induced Jurkat T-cell activation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:430861. [PMID: 23586039 PMCID: PMC3622291 DOI: 10.1155/2013/430861] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/28/2013] [Accepted: 02/13/2013] [Indexed: 01/04/2023]
Abstract
Interleukin- (IL-) 2 is the major growth factor for T-cell activation and proliferation. IL-2 has multiple functions in the regulation of immunological processes. Although most studies focus on T-cell immunomodulation, T-cell activation by IL-2 is the foundation of priming the feedback loop. Here, we investigated the effect of MAPK/ERK and PI3K/Akt signaling pathways on IL-2-induced cell activation and the regulatory mechanisms of upstream ubiquitin ligase Cbl-b and c-Cbl. Morphological analysis of Jurkat T cells was performed by cytospin preparations with Wright-Giemsa stain. CD25 expression on Jurkat T cells was determined by flow cytometry. Changes in cell activation proteins such as p-ERK, ERK, p-Akt, Akt, and ubiquitin ligase Casitas B-cell Lymphoma (Cbl) proteins were analyzed by western blot. Following IL-2-induced activation of Jurkat T cells, p-ERK expression was upregulated, while there was no change in p-Akt, ERK, or Akt expression. Thus, the MAPK/ERK signaling pathway, but not PI3K/Akt, was involved in IL-2-induced T-cell activation. Either using PD98059 (a specific inhibitor for p-ERK) or depletion of ERK with small interfering RNA (siRNA) reduced the expression of CD25. This study also showed that ubiquitin ligase proteins Cbl-b and c-Cbl might be involved in IL-2-induced Jurkat T-cell activation by negatively regulating the MAPK/ERK signaling pathway.
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Badr G, Mahmoud MH, Farhat K, Waly H, Al-Abdin OZ, Rabah DM. Maternal supplementation of diabetic mice with thymoquinone protects their offspring from abnormal obesity and diabetes by modulating their lipid profile and free radical production and restoring lymphocyte proliferation via PI3K/AKT signaling. Lipids Health Dis 2013; 12:37. [PMID: 23506302 PMCID: PMC3608164 DOI: 10.1186/1476-511x-12-37] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 03/15/2013] [Indexed: 01/12/2023] Open
Abstract
Background Epidemiological studies have shown that the offspring of mothers who experience diabetes mellitus during pregnancy are seven times more likely to develop health complications than the offspring of mothers who do not suffer from diabetes during pregnancy. The present study was designed to investigate whether supplementation of streptozotocin (STZ)-induced diabetic pregnant mice with thymoquinone (TQ) during pregnancy and lactation improves the risk of developing diabetic complications acquired by their offspring. Methods Three groups of pregnant female mice were used: non-diabetic control dams (CD), diabetic dams (DD), and diabetic dams supplemented with TQ (DD + TQ) during pregnancy and lactation (n = 10 female mice in each group). Results Our data demonstrated a marked decrease in the number of neonates born to DD, and these neonates showed a marked increase in their mean body weight (macrosomic pups) compared to those born to CD and DD + TQ. The induction of diabetes during pregnancy and lactation resulted in macrosomic pups with several postpartum complications, such as a marked increase in their levels of blood glucose, free radicals, plasma pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), and lipids, and a tendency toward abnormal obesity compared to the offspring of CD. By contrast, macrosomic offspring born to DD exhibited a marked reduction in plasma cytokine levels (IL-2, -4 and -7), an obvious reduction in the number of circulating lymphocytes, decreased proliferation of superantigen (SEB)-stimulated lymphocytes and aberrant AKT phosphorylation. Interestingly, the supplementation of DD with TQ during pregnancy and lactation had an obvious and significant effect on the number and mean body weight of neonates. Furthermore, TQ significantly restored the levels of blood glucose, insulin, free radicals, plasma cytokines, and lipids as well as lymphocyte proliferation in the offspring. Conclusions Our data suggest that the nutritional supplementation of DD with the natural antioxidant TQ during pregnancy and lactation protects their offspring from developing diabetic complications and preserves an efficient lymphocyte immune response later in life.
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Affiliation(s)
- Gamal Badr
- Princess Al-Johara Al-Ibrahim Center for Cancer Research, Prostate Cancer Research Chair, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
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Affiliation(s)
- Jeffrey C Rathmell
- Department of Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center, Duke University, Durham, NC 27710, USA.
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Wensveen FM, van Gisbergen KPJM, Eldering E. The fourth dimension in immunological space: how the struggle for nutrients selects high-affinity lymphocytes. Immunol Rev 2013; 249:84-103. [PMID: 22889217 DOI: 10.1111/j.1600-065x.2012.01156.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Lymphocyte activation via the antigen receptor is associated with radical shifts in metabolism and changes in requirements for nutrients and cytokines. Concomitantly, drastic changes occur in the expression of pro-and anti-apoptotic proteins that alter the sensitivity of lymphocytes to limiting concentrations of key survival factors. Antigen affinity is a primary determinant for the capacity of activated lymphocytes to access these vital resources. The shift in metabolic needs and the variable access to key survival factors is used by the immune system to eliminate activated low-affinity cells and to generate an optimal high-affinity response. In this review, we focus on the control of apoptosis regulators in activated lymphocytes by nutrients, cytokines, and costimulation. We propose that the struggle among individual clones that leads to the formation of high-affinity effector cell populations is in effect an 'invisible' fourth signal required for effective immune responses.
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Affiliation(s)
- Felix M Wensveen
- Department of Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands
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61
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Doan PL, Himburg HA, Helms K, Russell JL, Fixsen E, Quarmyne M, Harris JR, Deoliviera D, Sullivan JM, Chao NJ, Kirsch DG, Chute JP. Epidermal growth factor regulates hematopoietic regeneration after radiation injury. Nat Med 2013; 19:295-304. [PMID: 23377280 PMCID: PMC3594347 DOI: 10.1038/nm.3070] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 12/13/2012] [Indexed: 01/20/2023]
Abstract
The mechanisms which regulate HSC regeneration following myelosuppressive injury are not well understood. We identified epidermal growth factor (EGF) to be highly enriched in the bone marrow (BM) serum of mice bearing deletion of Bak and Bax in Tie2+ cells (Tie2Cre;Bak1−/−;Baxfl/− mice), which displayed radioprotection of the HSC pool and 100% survival following lethal dose total body irradiation (TBI). BM HSCs from wild type mice expressed functional EGFR and systemic administration of EGF promoted the recovery of the HSC pool in vivo and the improved survival of mice following TBI. Conversely, administration of erlotinib, an EGFR antagonist, significantly decreased both HSC regeneration and mice survival following TBI. VavCre;EGFRfl/+ mice also demonstrated delayed recovery of BM stem/progenitor cells following TBI compared to VavCre;EGFR+/+ mice. Mechanistically, EGF reduced radiation-induced apoptosis of HSCs and mediated this effect via repression of the proapoptotic protein, PUMA. EGFR signaling regulates HSC regeneration following myelosuppressive injury.
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Affiliation(s)
- Phuong L Doan
- Department of Medicine, Division of Hematologic Malignancies and Cellular Therapy, Durham, North Carolina, USA
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62
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Macintyre AN, Rathmell JC. Activated lymphocytes as a metabolic model for carcinogenesis. Cancer Metab 2013; 1:5. [PMID: 24280044 PMCID: PMC3834493 DOI: 10.1186/2049-3002-1-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/04/2012] [Indexed: 12/11/2022] Open
Abstract
Metabolic reprogramming is a key event in tumorigenesis to support cell growth, and cancer cells frequently become both highly glycolytic and glutamine dependent. Similarly, T lymphocytes (T cells) modify their metabolism after activation by foreign antigens to shift from an energetically efficient oxidative metabolism to a highly glycolytic and glutamine-dependent metabolic program. This metabolic transition enables T cell growth, proliferation, and differentiation. In both activated T cells and cancer cells metabolic reprogramming is achieved by similar mechanisms and offers similar survival and cell growth advantages. Activated T cells thus present a useful model with which to study the development of tumor metabolism. Here, we review the metabolic similarities and distinctions between activated T cells and cancer cells, and discuss both the common signaling pathways and master metabolic regulators that lead to metabolic rewiring. Ultimately, understanding how and why T cells adopt a cancer cell-like metabolic profile may identify new therapeutic strategies to selectively target tumor metabolism or inflammatory immune responses.
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Affiliation(s)
- Andrew N Macintyre
- Department of Pharmacology and Cancer Biology, Department of Immunology, Sarah W, Stedman Nutrition and Metabolism Center, Duke University, Durham, NC, 27710, USA.
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63
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Abstract
T cell activation leads to dramatic shifts in cell metabolism to protect against pathogens and to orchestrate the action of other immune cells. Quiescent T cells require predominantly ATP-generating processes, whereas proliferating effector T cells require high metabolic flux through growth-promoting pathways. Further, functionally distinct T cell subsets require distinct energetic and biosynthetic pathways to support their specific functional needs. Pathways that control immune cell function and metabolism are intimately linked, and changes in cell metabolism at both the cell and system levels have been shown to enhance or suppress specific T cell functions. As a result of these findings, cell metabolism is now appreciated as a key regulator of T cell function specification and fate. This review discusses the role of cellular metabolism in T cell development, activation, differentiation, and function to highlight the clinical relevance and opportunities for therapeutic interventions that may be used to disrupt immune pathogenesis.
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Affiliation(s)
- Nancie J MacIver
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA
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64
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Matched and mismatched metabolic fuels in lymphocyte function. Semin Immunol 2013; 24:405-13. [PMID: 23290889 DOI: 10.1016/j.smim.2012.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 12/10/2012] [Indexed: 12/23/2022]
Abstract
Immunological function requires metabolic support to suit the needs of lymphocytes at a variety of distinct differentiation and activation states. It is now evident that the signaling pathways that drive lymphocyte survival and activity can directly control cellular metabolism. This linkage provides a mechanism by which activation and specific signaling pathways provide a supply of appropriate and required nutrients to support cell functions in a pro-active supply rather than consumption-based metabolic model. In this way, the metabolism and fuel choices of lymphocytes are guided to specifically match the anticipated needs. If the fuel choice or metabolic pathways of lymphocytes are dysregulated, however, metabolic checkpoints can become activated to disrupt immunological function. These changes are now shown in several immunological diseases and may open new opportunities to selectively enhance or suppress specific immune functions through targeting of glucose, lipid, or amino acid metabolism.
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65
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66
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Procaccini C, Matarese G. Regulatory T cells, mTOR kinase, and metabolic activity. Cell Mol Life Sci 2012; 69:3975-87. [PMID: 22760498 PMCID: PMC11114691 DOI: 10.1007/s00018-012-1058-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/09/2012] [Accepted: 06/12/2012] [Indexed: 02/08/2023]
Abstract
The field that links immunity and metabolism is rapidly expanding. Apparently, non-immunological disorders such as obesity and type 2 diabetes have been linked to immune dysregulation, suggesting that metabolic alterations can be induced by or be a consequence of an altered self-immune tolerance. In this context, a key role is played by signaling systems acting as metabolic "sensors" linking energy/nutritional status to regulatory T (Treg) cell functions. We propose that a dynamic/oscillatory activity of intracellular metabolism, through mTOR modulation, might represent a shift in understanding the molecular mechanisms governing Treg cell tolerance. In particular, the decision between Treg cell proliferation and hyporesponsiveness arises from their ability to probe the extracellular milieu and, modulating the metabolic intracellular signaling, to determine different qualitative and quantitative functional outcomes.
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Affiliation(s)
- Claudio Procaccini
- Dipartimento di Medicina, Facoltà di Medicina, Università di Salerno, Baronissi Campus, 84081 Baronissi, Salerno Italy
- Laboratorio di Immunologia, Istituto di Endocrinologia e Oncologia Sperimentale, Consiglio Nazionale delle Ricerche (IEOS-CNR), 80131 Naples, Italy
- c/o Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli ‘‘Federico II”, 80131 Naples, Italy
| | - Giuseppe Matarese
- Dipartimento di Medicina, Facoltà di Medicina, Università di Salerno, Baronissi Campus, 84081 Baronissi, Salerno Italy
- Laboratorio di Immunologia, Istituto di Endocrinologia e Oncologia Sperimentale, Consiglio Nazionale delle Ricerche (IEOS-CNR), 80131 Naples, Italy
- c/o Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli ‘‘Federico II”, 80131 Naples, Italy
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Altman BJ, Rathmell JC. Metabolic stress in autophagy and cell death pathways. Cold Spring Harb Perspect Biol 2012; 4:a008763. [PMID: 22952396 DOI: 10.1101/cshperspect.a008763] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Growth factors and oncogenic kinases play important roles in stimulating cell growth during development and transformation. These processes have significant energetic and synthetic requirements and it is apparent that a central function of growth signals is to promote glucose metabolism to support these demands. Because metabolic pathways represent a fundamental aspect of cell proliferation and survival, there is considerable interest in targeting metabolism as a means to eliminate cancer. A challenge, however, is that molecular links between metabolic stress and cell death are poorly understood. Here we review current literature on how cells cope with metabolic stress and how autophagy, apoptosis, and necrosis are tightly linked to cell metabolism. Ultimately, understanding of the interplay between nutrients, autophagy, and cell death will be a key component in development of new treatment strategies to exploit the altered metabolism of cancer cells.
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Affiliation(s)
- Brian J Altman
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710, USA
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68
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Kashyap MP, Singh AK, Kumar V, Yadav DK, Khan F, Jahan S, Khanna VK, Yadav S, Pant AB. Pkb/Akt1 mediates Wnt/GSK3β/β-catenin signaling-induced apoptosis in human cord blood stem cells exposed to organophosphate pesticide monocrotophos. Stem Cells Dev 2012; 22:224-38. [PMID: 22897592 DOI: 10.1089/scd.2012.0220] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Inhibition mechanisms of protein kinase B (Pkb)/Akt and its consequences on related cell signaling were investigated in human umbilical cord blood stem cells (hUCBSCs) exposed to monocrotophos (MCP, an organophosphate pesticide). In silico data reveal that MCP interacts with kinase and c-terminal regulatory domains of Akt1, resulting into a total docking score of 5.2748 and also forms H-bond between its N-H and Thr-291 residue of Akt1, in addition to possessing several hydrophobic interactions. The main cause of Akt inhibition is considered to be the strong hydrogen bond between N-H and Thr-291, and hydrophobic interactions at Glu-234, and Asp-292 in the vicinity, which is usually occupied by the ribose of ATP, and interaction with residue Phe-161, thus leading to a significant conformational change in that particular portion of the protein. In silico data on Akt inhibition were confirmed by examining the downregulation of phosphorylated (Thr308/Ser493) Akt1 in MCP-exposed hUCBSCs. MCP-mediated altered levels of pAkt downstream targets viz., downregulated pGSK3β (Ser9), unchanged GSK3αβ, and upregulated levels of Bad, P(53), and caspase-9 further confirm the inhibition of pAkt. The cellular fate of such pAkt inhibition was confirmed by increased terminal deoxynucleotide transferase dUTP nick-end labeling positive cells, reduced mitochondrial membrane potential, and the activation of various MAPKs, proapoptotic markers-Bax, and caspases-9/3. Our data demonstrate that Akt1 plays a key role in MCP-induced apoptosis in hUCBSCs. We also identified that such cellular responses of human cord blood stem cells against MCP were due to strong binding and inhibition of kinase and AGC-Kinase-C terminal regulatory domains of Akt1.
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Affiliation(s)
- Mahendra P Kashyap
- In Vitro Toxicology Laboratory, Indian Institute of Toxicology Research, Council of Scientific & Industrial Research, Lucknow, India
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69
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Gottschalk S, Zwingmann C, Raymond VA, Hohnholt MC, Chan TS, Bilodeau M. Hepatocellular apoptosis in mice is associated with early upregulation of mitochondrial glucose metabolism. Apoptosis 2012; 17:143-53. [PMID: 22109881 DOI: 10.1007/s10495-011-0669-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hepatocyte death due to apoptosis is a hallmark of almost every liver disease. Manipulation of cell death regulatory steps during the apoptotic process is therefore an obvious goal of biomedical research. To clarify whether metabolic changes occur prior to the characteristic apoptotic events, we used ex vivo multinuclear NMR-spectroscopy to study metabolic pathways of [U-(13)C]glucose in mouse liver during Fas-induced apoptosis. We addressed whether these changes could be associated with protection against apoptosis afforded by Epidermal Growth Factor (EGF). Our results show that serum alanine and aspartate aminotransferase levels, caspase-3 activity, BID cleavage and changes in cellular energy stores were not observed before 3 h following anti-Fas injection. However, as early as 45 min after anti-Fas treatment, we observed upregulation of carbon entry (i.e. flux) from glucose into the Krebs-cycle via pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) (up to 139% and 123% of controls, respectively, P < 0.001). This was associated with increased glutathione synthesis. EGF treatment significantly attenuated Fas-induced apoptosis, liver injury and the late decrease in energy stores, as well as the early fluxes through PDH and PC which were comparable to untreated controls. Using ex vivo multinuclear NMR-spectroscopic analysis, we have shown that Fas receptor activation in mouse liver time-dependently affects specific metabolic pathways of glucose. These early upregulations in glucose metabolic pathways occur prior to any visible signs of apoptosis and may have the potential to contribute to the initiation of apoptosis by maintaining mitochondrial energy production and cellular glutathione stores.
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Affiliation(s)
- Sven Gottschalk
- Centre de recherche, Centre hospitalier du l'Université de Montréal, Hôpital Saint-Luc, Montréal, QC, H2X 1P1, Canada.
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70
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Morfouace M, Lalier L, Bahut M, Bonnamain V, Naveilhan P, Guette C, Oliver L, Gueguen N, Reynier P, Vallette FM. Comparison of spheroids formed by rat glioma stem cells and neural stem cells reveals differences in glucose metabolism and promising therapeutic applications. J Biol Chem 2012; 287:33664-74. [PMID: 22782899 DOI: 10.1074/jbc.m111.320028] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cancer stem cells (CSCs) are thought to be partially responsible for cancer resistance to current therapies and tumor recurrence. Dichloroacetate (DCA), a compound capable of shifting metabolism from glycolysis to glucose oxidation, via an inhibition of pyruvate dehydrogenase kinase was used. We show that DCA is able to shift the pyruvate metabolism in rat glioma CSCs but has no effect in rat neural stem cells. DCA forces CSCs into oxidative phosphorylation but does not trigger the production of reactive oxygen species and consecutive anti-cancer apoptosis. However, DCA, associated with etoposide or irradiation, induced a Bax-dependent apoptosis in CSCs in vitro and decreased their proliferation in vivo. The former phenomenon is related to DCA-induced Foxo3 and p53 expression, resulting in the overexpression of BH3-only proteins (Bad, Noxa, and Puma), which in turn facilitates Bax-dependent apoptosis. Our results demonstrate that a small drug available for clinical studies potentiates the induction of apoptosis in glioma CSCs.
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Affiliation(s)
- Marie Morfouace
- UMR INSERM 892-CNRS 6299, Centre de Recherche en Cancérologie Nantes-Angers, Nantes, France
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71
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Abstract
Recent studies of normal and neoplastic lymphocytes have revealed overlapping metabolic rewiring in activated T cells and Myc-transformed lymphocytes. Myc expression is attenuated in normal lymphocytes that return to the basal state, but Notch-activated or Myc-transformed lymphocytes persistently express Myc, which activates genes involved in glucose and glutamine metabolism. Although this difference could provide a therapeutic window for the treatment of cancers, the overlapping metabolic profiles suggest a potential for immunosuppression by metabolic inhibitors.
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Affiliation(s)
- Brian J Altman
- Abramson Family Cancer Research Institute, Abramson Cancer Center, Division of Hematology-Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Ryder C, McColl K, Zhong F, Distelhorst CW. Acidosis promotes Bcl-2 family-mediated evasion of apoptosis: involvement of acid-sensing G protein-coupled receptor Gpr65 signaling to Mek/Erk. J Biol Chem 2012; 287:27863-75. [PMID: 22685289 DOI: 10.1074/jbc.m112.384685] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acidosis arises in solid and lymphoid malignancies secondary to altered nutrient supply and utilization. Tumor acidosis correlates with therapeutic resistance, although the mechanism behind this effect is not fully understood. Here we show that incubation of lymphoma cell lines in acidic conditions (pH 6.5) blocks apoptosis induced by multiple cytotoxic metabolic stresses, including deprivation of glucose or glutamine and treatment with dexamethasone. We sought to examine the role of the Bcl-2 family of apoptosis regulators in this process. Interestingly, we found that acidic culture causes elevation of both Bcl-2 and Bcl-xL, while also attenuating glutamine starvation-induced elevation of p53-up-regulated modulator of apoptosis (PUMA) and Bim. We confirmed with knockdown studies that these shifts direct survival decisions during starvation and acidosis. Importantly, the promotion of a high anti- to pro-apoptotic Bcl-2 family member ratio by acidosis renders cells exquisitely sensitive to the Bcl-2/Bcl-xL antagonist ABT-737, suggesting that acidosis causes Bcl-2 family dependence. This dependence appears to be mediated, in part, by the acid-sensing G protein-coupled receptor, GPR65, via a MEK/ERK pathway.
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Affiliation(s)
- Christopher Ryder
- Department of Pharmacology, Case Western Reserve University School of Medicine, Case Comprehensive Cancer Center, and University Hospitals Case Medical Center, Cleveland, Ohio 44106, USA
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73
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Multiple myeloma exhibits novel dependence on GLUT4, GLUT8, and GLUT11: implications for glucose transporter-directed therapy. Blood 2012; 119:4686-97. [PMID: 22452979 DOI: 10.1182/blood-2011-09-377846] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Multiple myeloma is one of numerous malignancies characterized by increased glucose consumption, a phenomenon with significant prognostic implications in this disease. Few studies have focused on elucidating the molecular underpinnings of glucose transporter (GLUT) activation in cancer, knowledge that could facilitate identification of promising therapeutic targets. To address this issue, we performed gene expression profiling studies involving myeloma cell lines and primary cells as well as normal lymphocytes to uncover deregulated GLUT family members in myeloma. Our data demonstrate that myeloma cells exhibit reliance on constitutively cell surface-localized GLUT4 for basal glucose consumption, maintenance of Mcl-1 expression, growth, and survival. We also establish that the activities of the enigmatic transporters GLUT8 and GLUT11 are required for proliferation and viability in myeloma, albeit because of functionalities probably distinct from whole-cell glucose supply. As proof of principle regarding the therapeutic potential of GLUT-targeted compounds, we include evidence of the antimyeloma effects elicited against both cell lines and primary cells by the FDA-approved HIV protease inhibitor ritonavir, which exerts a selective off-target inhibitory effect on GLUT4. Our work reveals critical roles for novel GLUT family members and highlights a therapeutic strategy entailing selective GLUT inhibition to specifically target aberrant glucose metabolism in cancer.
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74
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Metabolic pathways in T cell fate and function. Trends Immunol 2012; 33:168-73. [PMID: 22342741 DOI: 10.1016/j.it.2012.01.010] [Citation(s) in RCA: 305] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 01/18/2012] [Accepted: 01/18/2012] [Indexed: 12/25/2022]
Abstract
T cell growth and function must be tightly regulated to provide protection against foreign pathogens, while avoiding autoimmunity and immunodeficiency. It is now apparent that T cell metabolism is highly dynamic and has a tremendous impact on the ability of T cells to grow, activate and differentiate. Specific metabolic pathways provide energy and biosynthetic precursors that must support specific cell functions, as effector, regulatory, memory, and alloreactive T cells have distinct metabolic needs in immunity and inflammation. Here, we review the signaling pathways that control metabolism and how the metabolic phenotypes of T cell subtypes integrate with T cell function. Ultimately, these metabolic differences may provide new opportunities to modulate the immune response and treat inflammatory and autoimmune diseases.
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Abstract
Mutations of the TP53 gene and dysregulation of the TP53 pathway are important in the pathogenesis of many human cancers, including lymphomas. Tumor suppression by p53 occurs via both transcription-dependent activities in the nucleus by which p53 regulates transcription of genes involved in cell cycle, DNA repair, apoptosis, signaling, transcription, and metabolism; and transcription-independent activities that induces apoptosis and autophagy in the cytoplasm. In lymphoid malignancies, the frequency of TP53 deletions and mutations is lower than in other types of cancer. Nonetheless, the status of TP53 is an independent prognostic factor in most lymphoma types. Dysfunction of TP53 with wild-type coding sequence can result from deregulated gene expression, stability, and activity of p53. To overcome TP53 pathway inactivation, therapeutic delivery of wild-type p53, activation of mutant p53, inhibition of MDM2-mediated degradation of p53, and activation of p53-dependent and -independent apoptotic pathways have been explored experimentally and in clinical trials. We review the mechanisms of TP53 dysfunction, recent advances implicated in lymphomagenesis, and therapeutic approaches to overcoming p53 inactivation.
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Inhibition of AKT2 enhances sensitivity to gemcitabine via regulating PUMA and NF-κB signaling pathway in human pancreatic ductal adenocarcinoma. Int J Mol Sci 2012; 13:1186-1208. [PMID: 22312312 PMCID: PMC3269746 DOI: 10.3390/ijms13011186] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 12/08/2011] [Accepted: 12/21/2011] [Indexed: 01/26/2023] Open
Abstract
Invasion, metastasis and resistance to conventional chemotherapeutic agents are obstacles to successful treatment of pancreatic cancer, and a better understanding of the molecular basis of this malignancy may lead to improved therapeutics. In the present study, we investigated whether AKT2 silencing sensitized pancreatic cancer L3.6pl, BxPC-3, PANC-1 and MIAPaCa-2 cells to gemcitabine via regulating PUMA (p53-upregulated modulator of apoptosis) and nuclear factor (NF)-κB signaling pathway. MTT, TUNEL, EMSA and NF-κB reporter assays were used to detect tumor cell proliferation, apoptosis and NF-κB activity. Western blotting was used to detect different protein levels. Xenograft of established tumors was used to evaluate primary tumor growth and apoptosis after treatment with gemcitabine alone or in combination with AKT2 siRNA. Gemcitabine activated AKT2 and NF-κB in MIAPaCa-2 and L3.6pl cells in vitro or in vivo, and in PANC-1 cells only in vivo. Gemcitabine only activated NF-κB in BxPC-3 cells in vitro. The presence of PUMA was necessary for gemcitabine-induced apoptosis only in BxPC-3 cells in vitro. AKT2 inhibition sensitized gemcitabine-induced apoptosis via PUMA upregulation in MIAPaCa-2 cells in vitro, and via NF-κB activity inhibition in L3.6pl cells in vitro. In PANC-1 and MIAPaCa-2 cells in vivo, AKT2 inhibition sensitized gemcitabine-induced apoptosis and growth inhibition via both PUMA upregulation and NF-κB inhibition. We suggest that AKT2 inhibition abrogates gemcitabine-induced activation of AKT2 and NF-κB, and promotes gemcitabine-induced PUMA upregulation, resulting in chemosensitization of pancreatic tumors to gemcitabine, which is probably an important strategy for the treatment of pancreatic cancer.
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Abstract
The metabolic changes that occur in a cancer cell have been studied for a few decades, but our appreciation of the complexity and importance of those changes is now being realized. The metabolic switch from oxidative phosphorylation to aerobic glycolysis provides intermediates for cell growth and division and is regulated by both oncogenes and tumor suppressor genes. The p53 tumor suppressor gene has long been shown to play key roles in responding to DNA damage, hypoxia, and oncogenic activation. However, now p53 has added the ability to mediate metabolic changes in cells through the regulation of energy metabolism and oxidative stress to its repertoire of activities. It is therefore the focus of this review to discuss the metabolic pathways regulated by p53 and their cooperation in controlling cancer cell metabolism.
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Coloff JL, Macintyre AN, Nichols AG, Liu T, Gallo CA, Plas DR, Rathmell JC. Akt-dependent glucose metabolism promotes Mcl-1 synthesis to maintain cell survival and resistance to Bcl-2 inhibition. Cancer Res 2011; 71:5204-13. [PMID: 21670080 DOI: 10.1158/0008-5472.can-10-4531] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most cancer cells utilize aerobic glycolysis, and activation of the phosphoinositide 3-kinase/Akt/mTOR pathway can promote this metabolic program to render cells glucose dependent. Although manipulation of glucose metabolism may provide a means to specifically eliminate cancer cells, mechanistic links between cell metabolism and apoptosis remain poorly understood. Here, we examined the role and metabolic regulation of the antiapoptotic Bcl-2 family protein Mcl-1 in cell death upon inhibition of Akt-induced aerobic glycolysis. In the presence of adequate glucose, activated Akt prevented the loss of Mcl-1 expression and protected cells from growth factor deprivation-induced apoptosis. Mcl-1 associated with and inhibited the proapoptotic Bcl-2 family protein Bim, contributing to cell survival. However, suppression of glucose metabolism led to induction of Bim, decreased expression of Mcl-1, and apoptosis. The proapoptotic Bcl-2/Bcl-xL/Bcl-w inhibitor, ABT-737, shows clinical promise, but Mcl-1 upregulation can promote resistance. Importantly, inhibition of glucose metabolism or mTORC1 overcame Mcl-1-mediated resistance in diffuse large B cell leukemic cells. Together these data show that Mcl-1 protein synthesis is tightly controlled by metabolism and that manipulation of glucose metabolism may provide a mechanism to suppress Mcl-1 expression and sensitize cancer cells to apoptosis.
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Affiliation(s)
- Jonathan L Coloff
- Departments of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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