701
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Watanabe M, Naraba H, Sakyo T, Kitagawa T. DNA damage-induced modulation of GLUT3 expression is mediated through p53-independent extracellular signal-regulated kinase signaling in HeLa cells. Mol Cancer Res 2010; 8:1547-57. [PMID: 20870738 DOI: 10.1158/1541-7786.mcr-10-0011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Many cancer cells exhibit increased rates of uptake and metabolism of glucose compared with normal cells. Glucose uptake in mammalian cells is mediated by the glucose transporter (GLUT) family. Here, we report that DNA-damaging anticancer agents such as Adriamycin and etoposide suppressed the expression of GLUT3, but not GLUT1, in HeLa cells and a tumorigenic HeLa cell hybrid. Suppression of GLUT3 expression determined by the real-time PCR was also evident with another DNA-damaging agent, camptothecin, which reduced the promoter's activity as determined with a luciferase-linked assay. The suppression by these agents seemed to be induced independently of p53, and it was evident when wild-type p53 was overproduced in these cells. In contrast, the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) kinase (MEK) inhibitor U0126 (but not the phosphoinositide 3-kinase inhibitor LY294002) prevented the drug-induced suppression as determined by reverse transcription-PCR and promoter assays. Furthermore, overexpression of GLUT3 in HeLa cell hybrids increased resistance to these drugs, whereas depletion of the gene by small interfering RNA rendered the cells more sensitive to the drugs, decreasing glucose consumption. The results suggest that DNA-damaging agents reduce GLUT3 expression in cancer cells through activation of the MEK-ERK pathway independently of p53, leading to cell death or apoptosis. The findings may contribute to the development of new chemotherapeutic drugs based on the GLUT3-dependent metabolism of glucose.
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Affiliation(s)
- Masaru Watanabe
- Department of Cell Biology and Molecular Pathology, Iwate Medical University, School of Pharmacy, 2-1-1 Nishitokuta, Yahaba, Shiwa, Iwate 028-3694, Japan
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702
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Dong X, Tang H, Hess KR, Abbruzzese JL, Li D. Glucose metabolism gene polymorphisms and clinical outcome in pancreatic cancer. Cancer 2010; 117:480-91. [PMID: 20845477 DOI: 10.1002/cncr.25612] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 07/29/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND Altered glucose metabolism is the most common metabolic hallmark of malignancies. The authors tested the hypothesis that glucose metabolism gene variations affect clinical outcome in pancreatic cancer. METHODS The authors retrospectively genotyped 26 single nucleotide polymorphisms from 5 glucose metabolism genes in 154 patients with localized disease and validated the findings in 552 patients with different stages of pancreatic adenocarcinoma. Association between genotypes and overall survival (OS) was evaluated using multivariate Cox proportional hazard regression models with adjustment for clinical predictors. RESULTS Glucokinase (GCK) IVS1 + 9652C > T and hexokinase 2 (HK2) N692N homozygous variants were significantly associated with reduced OS in the training set of 154 patients (P < .001). These associations were confirmed in the validation set of 552 patients and in the combined dataset of all 706 patients (P ≤ .001). In addition, HK2 R844K variant K allele was associated with a better survival in the validation set and the combined dataset (P ≤ .001). When data were further analyzed by disease stage, glutamine-fructose-6-phosphate transaminase (GFPT1) IVS14-3094T>C, HK2 N692N and R844K in patients with localized disease and GCK IVS1 + 9652C>T in patients with advanced disease were significant independent predictors for OS (P ≤ .001). Haplotype CGG of GPI and GCTATGG of HK2 were associated with better OS, respectively, with P values of .004 and .007. CONCLUSIONS The authors demonstrated that glucose metabolism gene polymorphisms affect clinical outcome in pancreatic cancer. These observations support a role of abnormal glucose metabolism in pancreatic carcinogenesis.
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Affiliation(s)
- Xiaoqun Dong
- Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 7703-4009, USA
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703
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Aller MA, Arias JI, Arias J. Pathological axes of wound repair: gastrulation revisited. Theor Biol Med Model 2010; 7:37. [PMID: 20840764 PMCID: PMC2945962 DOI: 10.1186/1742-4682-7-37] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 09/14/2010] [Indexed: 02/06/2023] Open
Abstract
Post-traumatic inflammation is formed by molecular and cellular complex mechanisms whose final goal seems to be injured tissue regeneration. In the skin -an exterior organ of the body- mechanical or thermal injury induces the expression of different inflammatory phenotypes that resemble similar phenotypes expressed during embryo development. Particularly, molecular and cellular mechanisms involved in gastrulation return. This is a developmental phase that delineates the three embryonic germ layers: ectoderm, endoderm and mesoderm. Consequently, in the post-natal wounded skin, primitive functions related with the embryonic mesoderm, i.e. amniotic and yolk sac-derived, are expressed. Neurogenesis and hematogenesis stand out among the primitive function mechanisms involved. Interestingly, in these phases of the inflammatory response, whose molecular and cellular mechanisms are considered as traces of the early phases of the embryonic development, the mast cell, a cell that is supposedly inflammatory, plays a key role. The correlation that can be established between the embryonic and the inflammatory events suggests that the results obtained from the research regarding both great fields of knowledge must be interchangeable to obtain the maximum advantage.
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Affiliation(s)
- Maria-Angeles Aller
- Surgery I Department, School of Medicine, Complutense University of Madrid, Madrid, Spain
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704
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Böhlig L, Friedrich M, Engeland K. p53 activates the PANK1/miRNA-107 gene leading to downregulation of CDK6 and p130 cell cycle proteins. Nucleic Acids Res 2010; 39:440-53. [PMID: 20833636 PMCID: PMC3025554 DOI: 10.1093/nar/gkq796] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The tumor suppressor p53 is a central regulator of cell-cycle arrest and apoptosis by acting as a transcription factor to regulate numerous genes. We identified all human p53-regulated mRNAs by microarray analyses and searched for protein-coding genes which contain intronic miRNAs. Among others, this analysis yielded the panthothenate kinase 1 (PANK1) gene and its intronic miRNA-107. We showed that miRNA-107 and PANK1 are coregulated by p53 in different cell systems. The PANK1 protein, which catalyzes the rate-limiting step of coenzyme A biosynthesis, is also upregulated by p53. We observed that p53 directly activates PANK1 and miRNA-107 transcription through a binding site in the PANK1 promoter. Furthermore, p53 is recruited to the PANK1 promoter after DNA damage. In order to get more insight into miRNA-107 function we investigated its potential target genes. Cell-cycle regulators are significantly enriched among predicted miRNA-107 targets. We found miRNA-107-dependent regulation of two important regulators of G(1)/S progression, CDK6 and the RB-related 2 gene RBL2 (p130). CDK6 and p130 proteins are downregulated upon miRNA-107 expression. Our results uncover a novel miRNA-dependent signaling pathway which leads to downregulation of cell cycle proteins in the absence of transcriptional repression.
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Affiliation(s)
- Levin Böhlig
- Department of Obstetrics and Gynecology, University of Leipzig, Leipzig, Germany
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705
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Chen B, Longtine MS, Sadovsky Y, Nelson DM. Hypoxia downregulates p53 but induces apoptosis and enhances expression of BAD in cultures of human syncytiotrophoblasts. Am J Physiol Cell Physiol 2010; 299:C968-76. [PMID: 20810912 DOI: 10.1152/ajpcell.00154.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hypoxia is commonly assigned a role in the placental dysfunction characteristic of preeclampsia and intrauterine growth restriction. We previously showed that hypoxia upregulates p53 and enhances apoptosis in primary cultures of human cytotrophoblasts. Here we tested the hypothesis that hypoxia also induces apoptosis in syncytiotrophoblasts by upregulation of p53. Primary cultures of human cytotrophoblasts that had differentiated into syncytiotrophoblasts by 52 h were exposed for ≤24 h to 20% or <1% oxygen in the presence or absence of staurosporine or the p53 modulators nutlin-3, pifithrin-α, and pifithrin-μ. Proteins were detected by Western blot analysis or immunofluorescence. Compared with 20% oxygen, exposure of syncytiotrophoblasts to <1% oxygen upregulated hypoxia-inducible factor (HIF)-1α and rapidly downregulated p53. Activity of p53 in hypoxic syncytiotrophoblasts was reduced by the higher expression of the negative p53 regulator MDMX and by the reduction of phosphorylation of p53 at Ser(392), which reduces p53 activity. Conversely, staurosporine, a kinase inhibitor, and nutlin-3, a drug that enhances p53 expression, both raised p53 levels and increased the rate of apoptosis in syncytiotrophoblasts compared with vehicle controls. Immunofluorescence staining showed p53 immunolocalized to both cytoplasm and nuclei of nutlin-3-exposed syncytiotrophoblasts. The hypoxia-induced apoptosis in syncytiotrophoblasts correlated with enhanced expression of the proapoptotic BAD and a reduced level of antiapoptotic BAD phosphorylated on Ser(112). We surmise that cell death induced by extreme hypoxia in syncytiotrophoblasts follows a non-p53-dependent pathway, unlike that of a nonhypoxic stimulus and unlike hypoxic cytotrophoblasts. We speculate that downregulation of p53 activity in response to hypoxia reduces or eliminates the apoptosis transduced by the p53 pathway in syncytiotrophoblasts, thereby limiting cell death and maintaining the integrity of this critical villous component.
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Affiliation(s)
- Baosheng Chen
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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706
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Resendis-Antonio O, Checa A, Encarnación S. Modeling core metabolism in cancer cells: surveying the topology underlying the Warburg effect. PLoS One 2010; 5:e12383. [PMID: 20811631 PMCID: PMC2928278 DOI: 10.1371/journal.pone.0012383] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 07/29/2010] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Alterations on glucose consumption and biosynthetic activity of amino acids, lipids and nucleotides are metabolic changes for sustaining cell proliferation in cancer cells. Irrevocable evidence of this fact is the Warburg effect which establishes that cancer cells prefers glycolysis over oxidative phosphorylation to generate ATP. Regulatory action over metabolic enzymes has opened a new window for designing more effective anti-cancer treatments. This enterprise is not trivial and the development of computational models that contribute to identifying potential enzymes for breaking the robustness of cancer cells is a priority. METHODOLOGY/PRINCIPAL FINDINGS This work presents a constraint-base modeling of the most experimentally studied metabolic pathways supporting cancer cells: glycolysis, TCA cycle, pentose phosphate, glutaminolysis and oxidative phosphorylation. To evaluate its predictive capacities, a growth kinetics study for Hela cell lines was accomplished and qualitatively compared with in silico predictions. Furthermore, based on pure computational criteria, we concluded that a set of enzymes (such as lactate dehydrogenase and pyruvate dehydrogenase) perform a pivotal role in cancer cell growth, findings supported by an experimental counterpart. CONCLUSIONS/SIGNIFICANCE Alterations on metabolic activity are crucial to initiate and sustain cancer phenotype. In this work, we analyzed the phenotype capacities emerged from a constructed metabolic network conformed by the most experimentally studied pathways sustaining cancer cell growth. Remarkably, in silico model was able to resemble the physiological conditions in cancer cells and successfully identified some enzymes currently studied by its therapeutic effect. Overall, we supplied evidence that constraint-based modeling constitutes a promising computational platform to: 1) integrate high throughput technology and establish a crosstalk between experimental validation and in silico prediction in cancer cell phenotype; 2) explore the fundamental metabolic mechanism that confers robustness in cancer; and 3) suggest new metabolic targets for anticancer treatments. All these issues being central to explore cancer cell metabolism from a systems biology perspective.
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707
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Fan X, Cheong N, Iliakis G. Initial characterization of a low-molecular-weight factor enhancing the checkpoint response. Radiat Res 2010; 174:424-35. [PMID: 20731590 DOI: 10.1667/rr2165.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In higher eukaryotes, DNA double-strand breaks (DSBs) induced by ionizing radiation activate checkpoints that delay progression through the cell cycle. Compared to delays in other phases of the cell cycle, delays induced in G(2) are longer and frequently correlate with resistance to killing by radiation. Therefore, modulation of the G(2) checkpoint offers a means to modulate cellular radiosensitivity. Although compounds are known that reduce the G(2) checkpoint and act as radiosensitizers, compounds enhancing this checkpoint have not been reported. Here we summarize evidence for a factor with such properties. We show that a highly radioresistant rat embryo fibroblast (REF) cell line displays a strong G(2) checkpoint partly as a result of a factor excreted into the growth medium by nonirradiated cells. Various tests indicate that this G(2)-arrest modulating activity (GAMA) is a small molecule showing detectable retention only after passing through filters with a molecular weight cutoff limit of less than 1,000 Da. GAMA is heat stable and resistant to treatment with proteases or nucleases. Electroelution tests show that GAMA is uncharged at neutral pH, a result that is in agreement with the observed failure to bind S- or Q-Sepharose. Investigations on the mechanism of GAMA function indicate ligand-receptor interactions and allow the classification of cells as producers, responders or both. Compounds with properties such as those of GAMA bridge intercellular communication with the DNA damage response and may function as radioprotectors.
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Affiliation(s)
- Xiaoxiang Fan
- University of Duisburg-Essen, Medical School, Institute of Medical Radiation Biology, 45122 Essen, Germany
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708
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The role of mitochondria in pulmonary vascular remodeling. J Mol Med (Berl) 2010; 88:1003-10. [PMID: 20734021 DOI: 10.1007/s00109-010-0670-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 08/04/2010] [Accepted: 08/06/2010] [Indexed: 02/08/2023]
Abstract
Pulmonary arterial hypertension (PAH) is characterized by a hyperproliferative and anti-apoptotic diathesis within the vascular wall of the resistance pulmonary arteries, leading to vascular lumen occlusion, right ventricular failure, and death. Most current therapies show poor efficacy due to emphasis on vasodilation (rather than proliferation/apoptosis) and a lack of specificity to the pulmonary circulation. The multiple molecular abnormalities described in PAH are diverse and seemingly unrelated, calling for therapies that attack comprehensive, integrative mechanisms. Similar abnormalities also occur in cancer where a cancer-specific metabolic switch toward a non-hypoxic glycolytic phenotype is thought to be not only a result of several primary molecular or genetic abnormalities but also underlie many aspects of its resistance to apoptosis. In this paper, we review the evidence and propose that a metabolic, mitochondria-based theory can be applied in PAH. A pulmonary artery smooth muscle cell mitochondrial remodeling could integrate a number of diverse molecular abnormalities described in PAH and respond by orchestrating a switch toward a cancer-like glycolytic phenotype that drives resistance to apoptosis; via redox and calcium signals, this mitochondrial remodeling may also regulate critical transcription factors like HIF-1 and nuclear factor of activated T cells that have been described to play an important role in PAH. Because mitochondria in pulmonary arteries are quite different from mitochondria in systemic arteries, they could form the basis of relatively selective PAH therapies. This metabolic theory of PAH could facilitate the development of novel diagnostic and selective therapeutic approaches in this disease that remains deadly.
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709
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Glycolytic flux occurs in Drosophila melanogaster recovering from camptothecin treatment. Anticancer Drugs 2010; 21:945-57. [PMID: 20717003 DOI: 10.1097/cad.0b013e32833e2f60] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Camptothecin (CPT) and CPT-derived drugs are widely used against gynaecological and colorectal cancers. On account of their mechanism of action these drugs target rapidly dividing cells and may have an adverse effect on normal tissues. We sought to investigate their impact on normal cells by using Drosophila as a model. We investigated the possible involvement of Drosophila homologue of p53 (Dmp53) and a member of the retinoblastoma binding protein 6 family, known as Snama. On account of its molecular features and experimental evidence gleaned from mammalian studies we propose Snama as a candidate in Dmp53 regulation. We have used proteomics and core molecular biology techniques on embryos and on adult flies. We found that flies that recover from CPT treatment display a metabolic programme characterized by glycolytic flux, depletion of Dmp53 and increase of Snama transcripts. When we introduced methyl pyruvate in the diet to bypass the glycolytic pathway, we noticed differential expression of Dmp53 and Snama and improvement in reproduction and embryonic development. The development of embryos into the pupal stage was significantly improved to 40% (P=0.02) when CPT was given to mothers in combination with methyl pyruvate. This investigation highlights the importance of energy production mechanisms in cells that recover from chemotherapy and differences between the metabolic programmes used by recovering cells and those adopted by cancer cells.
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710
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Phillips A, Teunisse A, Lam S, Lodder K, Darley M, Emaduddin M, Wolf A, Richter J, de Lange J, Verlaan-de Vries M, Lenos K, Böhnke A, Bartel F, Blaydes JP, Jochemsen AG. HDMX-L is expressed from a functional p53-responsive promoter in the first intron of the HDMX gene and participates in an autoregulatory feedback loop to control p53 activity. J Biol Chem 2010; 285:29111-27. [PMID: 20659896 DOI: 10.1074/jbc.m110.129726] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The p53 regulatory network is critically involved in preventing the initiation of cancer. In unstressed cells, p53 is maintained at low levels and is largely inactive, mainly through the action of its two essential negative regulators, HDM2 and HDMX. p53 abundance and activity are up-regulated in response to various stresses, including DNA damage and oncogene activation. Active p53 initiates transcriptional and transcription-independent programs that result in cell cycle arrest, cellular senescence, or apoptosis. p53 also activates transcription of HDM2, which initially leads to the degradation of HDMX, creating a positive feedback loop to obtain maximal activation of p53. Subsequently, when stress-induced post-translational modifications start to decline, HDM2 becomes effective in targeting p53 for degradation, thus attenuating the p53 response. To date, no clear function for HDMX in this critical attenuation phase has been demonstrated experimentally. Like HDM2, the HDMX gene contains a promoter (P2) in its first intron that is potentially inducible by p53. We show that p53 activation in response to a plethora of p53-activating agents induces the transcription of a novel HDMX mRNA transcript from the HDMX-P2 promoter. This mRNA is more efficiently translated than that expressed from the constitutive HDMX-P1 promoter, and it encodes a long form of HDMX protein, HDMX-L. Importantly, we demonstrate that HDMX-L cooperates with HDM2 to promote the ubiquitination of p53 and that p53-induced HDMX transcription from the P2 promoter can play a key role in the attenuation phase of the p53 response, to effectively diminish p53 abundance as cells recover from stress.
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Affiliation(s)
- Anna Phillips
- Southampton Cancer Research UK Centre, University of Southampton School of Medicine, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
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711
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Kawamura Y, Uchijima Y, Horike N, Tonami K, Nishiyama K, Amano T, Asano T, Kurihara Y, Kurihara H. Sirt3 protects in vitro-fertilized mouse preimplantation embryos against oxidative stress-induced p53-mediated developmental arrest. J Clin Invest 2010; 120:2817-28. [PMID: 20644252 DOI: 10.1172/jci42020] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 06/09/2010] [Indexed: 12/19/2022] Open
Abstract
Sirtuins are a phylogenetically conserved NAD+-dependent protein deacetylase/ADP-ribosyltransferase family implicated in diverse biological processes. Several family members localize to mitochondria, the function of which is thought to determine the developmental potential of preimplantation embryos. We have therefore characterized the role of sirtuins in mouse preimplantation development under in vitro culture conditions. All sirtuin members were expressed in eggs, and their expression gradually decreased until the blastocyst stage. Treatment with sirtuin inhibitors resulted in increased intracellular ROS levels and decreased blastocyst formation. These effects were recapitulated by siRNA-induced knockdown of Sirt3, which is involved in mitochondrial energy metabolism, and in Sirt3-/- embryos. The antioxidant N-acetyl-L-cysteine and low-oxygen conditions rescued these adverse effects. When Sirt3-knockdown embryos were transferred to pseudopregnant mice after long-term culture, implantation and fetal growth rates were decreased, indicating that Sirt3-knockdown embryos were sensitive to in vitro conditions and that the effect was long lasting. Further experiments revealed that maternally derived Sirt3 was critical. Sirt3 inactivation increased mitochondrial ROS production, leading to p53 upregulation and changes in downstream gene expression. The inactivation of p53 improved the developmental outcome of Sirt3-knockdown embryos, indicating that the ROS-p53 pathway was responsible for the developmental defects. These results indicate that Sirt3 plays a protective role in preimplantation embryos against stress conditions during in vitro fertilization and culture.
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Affiliation(s)
- Yumiko Kawamura
- Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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712
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Wlodkowic D, Skommer J, Darzynkiewicz Z. Cytometry in cell necrobiology revisited. Recent advances and new vistas. Cytometry A 2010; 77:591-606. [PMID: 20235235 PMCID: PMC2975392 DOI: 10.1002/cyto.a.20889] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Over a decade has passed since publication of the last review on "Cytometry in cell necrobiology." During these years we have witnessed many substantial developments in the field of cell necrobiology such as remarkable advancements in cytometric technologies and improvements in analytical biochemistry. The latest innovative platforms such as laser scanning cytometry, multispectral imaging cytometry, spectroscopic cytometry, and microfluidic Lab-on-a-Chip solutions rapidly emerge as highly advantageous tools in cell necrobiology studies. Furthermore, we have recently gained substantial knowledge on alternative cell demise modes such as caspase-independent apoptosis-like programmed cell death (PCD), autophagy, necrosis-like PCD, or mitotic catastrophe, all with profound connotations to pathogenesis and treatment. Although detection of classical, caspase-dependent apoptosis is still the major ground for the advancement of cytometric techniques, there is an increasing demand for novel analytical tools to rapidly quantify noncanonical modes of cell death. This review highlights the key developments warranting a renaissance and evolution of cytometric techniques in the field of cell necrobiology.
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Affiliation(s)
- Donald Wlodkowic
- The Bioelectronics Research Centre, University of Glasgow, Glasgow, United Kingdom.
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713
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Ohi R. Kip3-ing kinetochores clustered. Cell Cycle 2010; 9:2497. [PMID: 20647749 DOI: 10.4161/cc.9.13.12274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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714
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Farnebo M, Bykov VJN, Wiman KG. The p53 tumor suppressor: a master regulator of diverse cellular processes and therapeutic target in cancer. Biochem Biophys Res Commun 2010; 396:85-9. [PMID: 20494116 DOI: 10.1016/j.bbrc.2010.02.152] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 01/05/2023]
Abstract
The tumor suppressor p53 has been implicated in a growing number of biological processes, including cell cycle arrest, senescence, apoptosis, autophagy, metabolism, and aging. Activation of p53 in response to oncogenic stress eliminates nascent tumor cells by apoptosis or senescence. p53 is regulated at the protein level by posttranslational modifications such as phosphorylation and acetylation. A p53 antisense gene, Wrap53, enhances p53 mRNA levels via the 5'UTR. Lack of Wrap53 transcripts that overlap with p53 abrogates the p53 DNA damage response. Around half of all human tumors carry p53 mutation that disrupt p53 specific DNA binding, and transcriptional transactivation of target genes. Reactivation of mutant p53 is a promising strategy for novel cancer therapy. The small molecule PRIMA-1 restores wild type conformation and DNA binding to mutant p53, induces mutant p53-dependent apoptosis, and inhibits tumor growth in vivo. The PRIMA-1 analog APR-246 is currently tested in a phase I clinical trial. Improved understanding of the p53 pathway should lead to better diagnosis and treatment of cancer in the future.
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Affiliation(s)
- Marianne Farnebo
- Dept. of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
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715
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Bailey SG, Sanchez-Elsner T, Stephanou A, Cragg MS, Townsend PA. Regulating the genome surveillance system: miRNAs and the p53 super family. Apoptosis 2010; 15:541-52. [PMID: 20091234 DOI: 10.1007/s10495-010-0456-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The p53 gene super family consists of three members; TP53, TP63 and TP73, encoding proteins p53, p63 and p73. Whilst p63 appears to have an essential role in embryonic development with a less clear role in carcinogenesis, irregularities in p53 and p73 signalling are implicated in tumour formation. As such, p53 is a tumour suppressor which is mutated in over 50% cancers and p73 was recently formally classified as a tumour suppressor based on data showing p73 deficient mice generate spontaneous tumours similar to those observed in p53 null mice. Dysregulation of both p53 and p73 has been correlated with cancer progression in many cell types and although mutation of these genes is often observed, some form of p53/p73 deregulation likely occurs in all tumour cells. The discovery that complementary micro RNAs (miRNAs) are able to target both of these genes provides a potential new means of perturbing p53/p73 signalling networks in cancer cells. Here we summarise the current literature regarding the involvement of miRNAs in the modulation of p53 family proteins and cancer development and detail the use of in silico methods to reveal key miRNA targets.
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Affiliation(s)
- Sarah G Bailey
- School of Medicine, University of Southampton, Southampton, SO16 6YD, UK
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716
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Korotchkina LG, Leontieva OV, Bukreeva EI, Demidenko ZN, Gudkov AV, Blagosklonny MV. The choice between p53-induced senescence and quiescence is determined in part by the mTOR pathway. Aging (Albany NY) 2010; 2:344-52. [PMID: 20606252 PMCID: PMC2919254 DOI: 10.18632/aging.100160] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Transient induction of p53 can cause reversible quiescence and irreversible senescence. Using nutlin-3a (a small molecule that activates p53 without causing DNA damage), we have previously identified cell lines in which nutlin-3a caused quiescence. Importantly, nutlin-3a caused quiescence by actively suppressing the senescence program (while still causing cell cycle arrest). Noteworthy, in these cells nutlin-3a inhibited the mTOR (mammalian Target of Rapamycin) pathway, which is known to be involved in the senescence program. Here we showed that shRNA-mediated knockdown of TSC2, a negative regulator of mTOR, partially converted quiescence into senescence in these nutlin-arrested cells. In accord, in melanoma cell lines and mouse embryo fibroblasts, which easily undergo senescence in response to p53 activation, nutlin-3a failed to inhibit mTOR. In these senescence-prone cells, the mTOR inhibitor rapamycin converted nutlin-3a-induced senescence into quiescence. We conclude that status of the mTOR pathway can determine, at least in part, the choice between senescence and quiescence in p53-arrested cells.
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Affiliation(s)
- Lioubov G Korotchkina
- Department of Cell Stress Biology, Roswell Park Cancer Institute, BLSC, L3-312, Buffalo, NY 14263, USA
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717
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Podo F, Buydens LMC, Degani H, Hilhorst R, Klipp E, Gribbestad IS, Van Huffel S, van Laarhoven HWM, Luts J, Monleon D, Postma GJ, Schneiderhan-Marra N, Santoro F, Wouters H, Russnes HG, Sørlie T, Tagliabue E, Børresen-Dale AL. Triple-negative breast cancer: present challenges and new perspectives. Mol Oncol 2010; 4:209-29. [PMID: 20537966 PMCID: PMC5527939 DOI: 10.1016/j.molonc.2010.04.006] [Citation(s) in RCA: 229] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 04/16/2010] [Indexed: 12/28/2022] Open
Abstract
Triple-negative breast cancers (TNBC), characterized by absence of estrogen receptor (ER), progesterone receptor (PR) and lack of overexpression of human epidermal growth factor receptor 2 (HER2), are typically associated with poor prognosis, due to aggressive tumor phenotype(s), only partial response to chemotherapy and present lack of clinically established targeted therapies. Advances in the design of individualized strategies for treatment of TNBC patients require further elucidation, by combined 'omics' approaches, of the molecular mechanisms underlying TNBC phenotypic heterogeneity, and the still poorly understood association of TNBC with BRCA1 mutations. An overview is here presented on TNBC profiling in terms of expression signatures, within the functional genomic breast tumor classification, and ongoing efforts toward identification of new therapy targets and bioimaging markers. Due to the complexity of aberrant molecular patterns involved in expression, pathological progression and biological/clinical heterogeneity, the search for novel TNBC biomarkers and therapy targets requires collection of multi-dimensional data sets, use of robust multivariate data analysis techniques and development of innovative systems biology approaches.
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Affiliation(s)
- Franca Podo
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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718
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Hockenbery DM. Targeting mitochondria for cancer therapy. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:476-489. [PMID: 20213841 DOI: 10.1002/em.20552] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Several recent insights into the roles of mitochondria in cancer have renewed efforts to develop nongenotoxic therapies targeting mitochondrial proteins and functions. Mitochondria are central hubs for intrinsic apoptotic pathways that are activated by cellular stress and injury, and as a consequence, cancers often have defects in these pathways. Bcl-2, the first identified regulator of apoptotic cell deaths, was discovered as an oncogene in human cancers. BCL-2 inhibits mitochondrial pathways of apoptosis through local effects at mitochondrial and endoplasmic reticulum membranes. Increased expression of BCL-2 and the related antiapoptotic proteins BCL-X(L), MCL-1, and BCL-W occurs in significant subsets of common cancer types (Table I) and is generally correlated with poor response. Although incomplete, the emerging understanding of BCL-2 functions through structural, biochemical, and organelle physiology studies has provided paths for targeting BCL-2 with small molecules. Cancer cells also exhibit metabolic differences with their normal cell counterparts, including aerobic glycolysis, known as the Warburg effect, mitochondrial membrane hyperpolarization, and unusual dependence on nutrient substrates such as glucose and glutamine. This knowledge has prompted reexamination of the potential cancer selectivity of previously identified mitochondriotoxic compounds, including approved drugs for other indications, and screening programs to identify new compounds with mitochondrial activities.
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719
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Molchadsky A, Rivlin N, Brosh R, Rotter V, Sarig R. p53 is balancing development, differentiation and de-differentiation to assure cancer prevention. Carcinogenesis 2010; 31:1501-8. [DOI: 10.1093/carcin/bgq101] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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720
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Salminen A, Kaarniranta K. Glycolysis links p53 function with NF-kappaB signaling: impact on cancer and aging process. J Cell Physiol 2010; 224:1-6. [PMID: 20301205 DOI: 10.1002/jcp.22119] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In 1930, Otto Warburg observed that cancer cells produce an increased amount of their energy through aerobic glycolysis and subsequently, this was called the Warburg effect. During aging, the capacity for mitochondrial respiration clearly declines and aerobic glycolysis appears to compensate for the deficiency in oxidative metabolism. This shift in energy production, both in aging and cancer, could protect from the toxic effects of oxygen free radicals whereas increased glycolysis can have adverse effects. It was recently demonstrated that the glycolysis-linked protein O-glycosylation can potentiate the catalytic activity of IKK beta and subsequently trigger NF-kappaB signaling. It seems that tumor suppressor oncogene p53 has an important role in the regulation of protein O-glycosylation since p53 is a potent inhibitor of glycolysis, for example, via TIGAR protein expression. Aging is known to repress the function of p53 and this could enhance glycolysis and NF-kappaB signaling. We will discuss the role of p53 in the regulation of glycolysis-dependent activation of NF-kappaB signaling in both cancer and aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Kuopio, Kuopio, Finland.
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721
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Smeets SJ, van der Plas M, Schaaij-Visser TB, van Veen EA, van Meerloo J, Braakhuis BJ, Steenbergen RD, Brakenhoff RH. Immortalization of oral keratinocytes by functional inactivation of the p53 and pRb pathways. Int J Cancer 2010; 128:1596-605. [DOI: 10.1002/ijc.25474] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 05/06/2010] [Indexed: 12/13/2022]
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722
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Eby KG, Rosenbluth JM, Mays DJ, Marshall CB, Barton CE, Sinha S, Johnson KN, Tang L, Pietenpol JA. ISG20L1 is a p53 family target gene that modulates genotoxic stress-induced autophagy. Mol Cancer 2010; 9:95. [PMID: 20429933 PMCID: PMC2873442 DOI: 10.1186/1476-4598-9-95] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 04/29/2010] [Indexed: 01/28/2023] Open
Abstract
Background Autophagy is characterized by the sequestration of cytoplasm and organelles into multimembrane vesicles and subsequent degradation by the cell's lysosomal system. It is linked to many physiological functions in human cells including stress response, protein degradation, organelle turnover, caspase-independent cell death and tumor suppression. Malignant transformation is frequently associated with deregulation of autophagy and several tumor suppressors can modulate autophagic processes. The tumor suppressor p53 can induce autophagy after metabolic or genotoxic stress through transcriptionally-dependent and -independent mechanisms. In this study we expand on the former mechanism by functionally characterizing a p53 family target gene, ISG20L1 under conditions of genotoxic stress. Results We identified a p53 target gene, ISG20L1, and show that transcription of the gene can be regulated by all three p53 family members (p53, p63, and p73). We generated an antibody to ISG20L1 and found that it localizes to the nucleolar and perinucleolar regions of the nucleus and its protein levels increase in a p53- and p73-dependent manner after various forms of genotoxic stress. When ectopically expressed in epithelial cancer-derived cell lines, ISG20L1 expression decreased clonogenic survival without a concomitant elevation in apoptosis and this effect was partially rescued in cells that were ATG5 deficient. Knockdown of ISG20L1 did not alter 5-FU induced apoptosis as assessed by PARP and caspase-3 cleavage, sub-G1 content, and DNA laddering. Thus, we investigated the role of ISG20L1 in autophagy, a process commonly associated with type II cell death, and found that ISG20L1 knockdown decreased levels of autophagic vacuoles and LC3-II after genotoxic stress as assessed by electron microscopy, biochemical, and immunohistochemical measurements of LC3-II. Conclusions Our identification of ISG20L1 as a p53 family target and discovery that modulation of this target can regulate autophagic processes further strengthens the connection between p53 signaling and autophagy. Given the keen interest in targeting autophagy as an anticancer therapeutic approach in tumor cells that are defective in apoptosis, investigation of genes and signaling pathways involved in cell death associated with autophagy is critical.
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Affiliation(s)
- Kathryn G Eby
- Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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723
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Lu X, Masson E. Silver-Promoted Desilylation Catalyzed by Ortho- and Allosteric Cucurbiturils. Org Lett 2010; 12:2310-3. [DOI: 10.1021/ol100667z] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaoyong Lu
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701
| | - Eric Masson
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701
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724
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Ziebart T, Walenta S, Kunkel M, Reichert TE, Wagner W, Mueller-Klieser W. Metabolic and proteomic differentials in head and neck squamous cell carcinomas and normal gingival tissue. J Cancer Res Clin Oncol 2010; 137:193-9. [PMID: 20383719 DOI: 10.1007/s00432-010-0875-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 03/26/2010] [Indexed: 12/21/2022]
Abstract
PURPOSE A high lactate content in malignant head and neck cancer (Head and neck squamous cell carcinomas, HNSCC) is associated with a higher risk of metastatic spread and lower overall patient survival. However, until present, the underlying mechanisms are not clearly understood. Here, a systematic comparison of glucose metabolism in HNSCC and homologous normal tissue is presented for the first time. METHODS The concentrations of glucose, lactate and ATP were measured in cryobiopsies of 29 human HNSCC and of 9 normal mucosa using bioluminescence imaging. The protein expression of lactate dehydrogenase (LDH) was analyzed by Western blotting. RESULTS Tumors own a higher content of lactate and LDH in comparison with normal tissues. However, within the tumor group, the grade of LDH expression shows substantially strong variation and overlap with normal values. Furthermore, LDH expression was not correlated with tumor lactate content. Investigating a small subpopulation, patients with a short-term survival had significantly higher tumor lactate levels compared to patients with long-term survival. CONCLUSIONS The data provide clear evidence of an enhanced glycolysis in tumors compared to normal tissue. This may partially but not completely attributable to an elevated expression of LDH. High tumor lactate levels may be predictive for restricted patient survival. In conclusion, lactate measurements, for example non-invasively with MRT, should be advanced for use in clinical routine as a supportive tool for tumor diagnosis and prognosis.
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Affiliation(s)
- Thomas Ziebart
- Department of Oral and Maxillofacial Surgery, University Medical Center of the Johannes Gutenberg-University of Mainz, 55131 Mainz, Germany
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725
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726
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The role of p53 in glucose metabolism. Curr Opin Cell Biol 2010; 22:186-91. [DOI: 10.1016/j.ceb.2009.12.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 02/04/2023]
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727
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Phosphate-activated glutaminase (GLS2), a p53-inducible regulator of glutamine metabolism and reactive oxygen species. Proc Natl Acad Sci U S A 2010; 107:7461-6. [PMID: 20351271 DOI: 10.1073/pnas.1002459107] [Citation(s) in RCA: 475] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We identified a p53 target gene, phosphate-activated mitochondrial glutaminase (GLS2), a key enzyme in conversion of glutamine to glutamate, and thereby a regulator of glutathione (GSH) synthesis and energy production. GLS2 expression is induced in response to DNA damage or oxidative stress in a p53-dependent manner, and p53 associates with the GLS2 promoter. Elevated GLS2 facilitates glutamine metabolism and lowers intracellular reactive oxygen species (ROS) levels, resulting in an overall decrease in DNA oxidation as determined by measurement of 8-OH-dG content in both normal and stressed cells. Further, siRNA down-regulation of either GLS2 or p53 compromises the GSH-dependent antioxidant system and increases intracellular ROS levels. High ROS levels following GLS2 knockdown also coincide with stimulation of p53-induced cell death. We propose that GLS2 control of intracellular ROS levels and the apoptotic response facilitates the ability of p53 to protect cells from accumulation of genomic damage and allows cells to survive after mild and repairable genotoxic stress. Indeed, overexpression of GLS2 reduces the growth of tumor cells and colony formation. Further, compared with normal tissue, GLS2 expression is reduced in liver tumors. Thus, our results provide evidence for a unique metabolic role for p53, linking glutamine metabolism, energy, and ROS homeostasis, which may contribute to p53 tumor suppressor function.
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728
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Vilborg A, Wilhelm MT, Wiman KG. Regulation of tumor suppressor p53 at the RNA level. J Mol Med (Berl) 2010; 88:645-52. [PMID: 20306257 DOI: 10.1007/s00109-010-0609-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 02/22/2010] [Accepted: 02/24/2010] [Indexed: 01/07/2023]
Abstract
p53 is a key tumor suppressor that triggers cell cycle arrest, senescence, or apoptosis in response to cellular stress. Frequent p53 mutation in human tumors allows survival, sustained growth, and tumor progression. p53 is expressed at low levels under normal conditions, due to rapid protein turnover. Stress signaling induces p53 protein stabilization through phosphorylation and other post-translational modifications. However, recent studies have demonstrated critical regulation of p53 at the mRNA level, mediated via both the 5'UTR and the 3'UTR and affecting both the stability and the translation efficiency of the p53 mRNA. Both proteins and microRNAs have been implicated in such regulation. The p53 target gene Wig-1 encodes a zinc finger protein that binds to double-stranded RNA and enhances p53 mRNA stability by binding to the 3'UTR in a positive feedback loop. Here, we shall summarize current knowledge about regulation of the p53 mRNA and discuss possible implications for cancer therapy.
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Affiliation(s)
- Anna Vilborg
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
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729
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Mann PB, Jiang W, Zhu Z, Wolfe P, McTiernan A, Thompson HJ. Wheel running, skeletal muscle aerobic capacity and 1-methyl-1-nitrosourea induced mammary carcinogenesis in the rat. Carcinogenesis 2010; 31:1279-83. [PMID: 20299525 DOI: 10.1093/carcin/bgq063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Emerging evidence indicates that intrinsic differences and induced changes in aerobic capacity are probably to play a critical role in the development of chronic diseases like cancer. This study was initiated: (i) to determine how citrate synthase activity, which is routinely used as a marker of aerobic capacity and mitochondrial density in skeletal muscle, was affected by voluntary running on either a motorized activity wheel or a non-motorized free wheel and (ii) to investigate the association between aerobic capacity and the carcinogenic response induced in the mammary gland by intraperitoneal injection of 1-methyl-1-nitrosurea. Overall, wheel running reduced cancer incidence (96 versus 72%, P = 0.0006) and the number of cancers per animal (2.84 versus 1.78, P < 0.0001) and induced citrate synthase activity (276 versus 353 U/mg, P < 0.0001, sedentary control versus wheel running,respectively). Both motorized and free wheel running increased citrate synthase activity (373 +/- 24, 329 +/- 11 and 276 +/- 9 U/mg protein, P < 0.0001) and reduced the average number of cancers per rat (2.84, 1.96 and 1.63, P < 0.01), sedentary control, free wheel and motorized wheel, respectively. However, regression analyses failed to provide evidence of a significant association between citrate synthase activity and either cancer incidence or cancer multiplicity. Citrate synthase activity is a single measure in a complex pathway that determines aerobic capacity. The multifaceted nature of intrinsic and inducible aerobic capacity limits the usefulness of citrate synthase activity alone in elucidating the relationship between aerobic capacity and the carcinogenic response.
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Affiliation(s)
- Phillip B Mann
- Cancer Prevention Laboratory, Colorado State University, 1173 Campus Delivery, Fort Collins, CO 80523, USA
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730
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Animal models of mitochondrial DNA transactions in disease and ageing. Exp Gerontol 2010; 45:489-502. [PMID: 20123011 DOI: 10.1016/j.exger.2010.01.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 01/11/2010] [Accepted: 01/26/2010] [Indexed: 11/21/2022]
Abstract
Mitochondrial DNA (mtDNA) transactions, processes that include mtDNA replication, repair, recombination and transcription constitute the initial stages of mitochondrial biogenesis, and are at the core of understanding mitochondrial biology and medicine. All of the protein players are encoded in nuclear genes: some are proteins with well-known functions in the nucleus, others are well-known mitochondrial proteins now ascribed new functions, and still others are newly discovered factors. In this article we review recent advances in the field of mtDNA transactions with a special focus on physiological studies. In particular, we consider the expression of variant proteins, or altered expression of factors involved in these processes in powerful model organisms, such as Drosophila melanogaster and the mouse, which have promoted recognition of the broad relevance of oxidative phosphorylation defects resulting from improper maintenance of mtDNA. Furthermore, the animal models recapitulate many phenotypes related to human ageing and a variety of different diseases, a feature that has enhanced our understanding of, and inspired theories about, the molecular mechanisms of such biological processes.
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731
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Abstract
In this issue of Molecular Cell, Ide et al. (2009) have identified the enzyme guanidinoacetate methyltransferase (GAMT) that regulates creatine metabolism as a p53 target involved in apoptosis, reactive oxygen species (ROS), and fatty acid metabolism.
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Affiliation(s)
- Yan Zhu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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732
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Korolchuk VI, Menzies FM, Rubinsztein DC. Mechanisms of cross-talk between the ubiquitin-proteasome and autophagy-lysosome systems. FEBS Lett 2009; 584:1393-8. [PMID: 20040365 DOI: 10.1016/j.febslet.2009.12.047] [Citation(s) in RCA: 426] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 12/22/2009] [Accepted: 12/23/2009] [Indexed: 11/15/2022]
Abstract
The ubiquitin proteasome system (UPS) and macroautophagy (hereafter called autophagy) were, for a long time, regarded as independent degradative pathways with few or no points of interaction. This view started to change recently, in the light of findings that have suggested that ubiquitylation can target substrates for degradation via both pathways. Moreover, perturbations in the flux through either pathway have been reported to affect the activity of the other system, and a number of mechanisms have been proposed to rationalise the link between the UPS and autophagy. Here we critically review these findings and outline some outstanding issues that still await clarification.
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Affiliation(s)
- Viktor I Korolchuk
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK
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733
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Morselli E, Galluzzi L, Kepp O, Criollo A, Maiuri MC, Tavernarakis N, Madeo F, Kroemer G. Autophagy mediates pharmacological lifespan extension by spermidine and resveratrol. Aging (Albany NY) 2009; 1:961-70. [PMID: 20157579 PMCID: PMC2815753 DOI: 10.18632/aging.100110] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 12/22/2009] [Indexed: 12/22/2022]
Abstract
Although
autophagy has widely been conceived as a self-destructive mechanism that
causes cell death, accumulating evidence suggests that autophagy usually
mediates cytoprotection, thereby avoiding the apoptotic or necrotic demise
of stressed cells. Recent evidence produced by our groups demonstrates that
autophagy is also involved in pharmacological manipulations that increase
longevity. Exogenous supply of the polyamine spermidine can prolong the
lifespan of (while inducing autophagy in) yeast, nematodes and flies.
Similarly, resveratrol can trigger autophagy in cells from different
organisms, extend lifespan in nematodes, and ameliorate the fitness of
human cells undergoing metabolic stress. These beneficial effects are lost
when essential autophagy modulators are genetically or pharmacologically
inactivated, indicating that autophagy is required for the cytoprotective
and/or anti-aging effects of spermidine and resveratrol. Genetic and
functional studies indicate that spermidine inhibits histone acetylases,
while resveratrol activates the histone deacetylase Sirtuin 1 to confer
cytoprotection/longevity. Although it remains elusive whether the same
histones (or perhaps other nuclear or cytoplasmic proteins) act as the downstream
targets of spermidine and resveratrol, these results point to an essential
role of protein hypoacetylation in autophagy control and in the regulation
of longevity.
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734
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Lambert JMR, Moshfegh A, Hainaut P, Wiman KG, Bykov VJN. Mutant p53 reactivation by PRIMA-1MET induces multiple signaling pathways converging on apoptosis. Oncogene 2009; 29:1329-38. [PMID: 19946333 DOI: 10.1038/onc.2009.425] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The low molecular weight compound PRIMA-1(MET) reactivates mutant p53 and triggers mutant p53-dependent apoptosis in human tumor cells. We investigated the effect of PRIMA-1(MET) on global gene expression using microarray analysis of Saos-2 cells expressing His273 mutant p53 and parental p53 null Saos-2 cells. PRIMA-1(MET) affected transcription of a significantly larger number of genes in the mutant p53-expressing cells compared to the p53 null cells. Genes affected by PRIMA-1(MET) in a mutant p53-dependent manner include the cell-cycle regulators GADD45B and 14-3-3gamma and the pro-apoptotic Noxa. Several of the affected genes are known p53 target genes and/or contain p53 DNA-binding motifs. We also found mutant p53-dependent disruption of the cytoskeleton, as well as transcriptional activation of the XBP1 gene and cleavage of its mRNA, a marker for endoplasmic reticulum stress. Our data show that PRIMA-1(MET) induces apoptosis through multiple transcription-dependent and -independent pathways. Such integral engagement of multiple pathways leading to apoptosis is consistent with restoration of wild-type properties to mutant p53 and is likely to reduce the risk of drug resistance development in clinical applications of PRIMA-1(MET).
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Affiliation(s)
- J M R Lambert
- Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm, Sweden
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735
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Calin GA, Sevignani C, Dumitru CD, Hyslop T, Noch E, Yendamuri S, Shimizu M, Rattan S, Bullrich F, Negrini M, Croce CM. Human microRNA genes are frequently located at fragile sites and genomic regions involved in cancers. Proc Natl Acad Sci U S A 2004; 101:2999-3004. [PMID: 14973191 PMCID: PMC365734 DOI: 10.1073/pnas.0307323101] [Citation(s) in RCA: 3048] [Impact Index Per Article: 152.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A large number of tiny noncoding RNAs have been cloned and named microRNAs (miRs). Recently, we have reported that miR-15a and miR-16a, located at 13q14, are frequently deleted and/or down-regulated in patients with B cell chronic lymphocytic leukemia, a disorder characterized by increased survival. To further investigate the possible involvement of miRs in human cancers on a genome-wide basis, we have mapped 186 miRs and compared their location to the location of previous reported nonrandom genetic alterations. Here, we show that miR genes are frequently located at fragile sites, as well as in minimal regions of loss of heterozygosity, minimal regions of amplification (minimal amplicons), or common breakpoint regions. Overall, 98 of 186 (52.5%) of miR genes are in cancer-associated genomic regions or in fragile sites. Moreover, by Northern blotting, we have shown that several miRs located in deleted regions have low levels of expression in cancer samples. These data provide a catalog of miR genes that may have roles in cancer and argue that the full complement of miRs in a genome may be extensively involved in cancers.
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Affiliation(s)
- George Adrian Calin
- Department of Microbiology and Immunology, Division of Clinical Pharmacology, Biostatistics Section, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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