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Miladinovic T, Nashed MG, Singh G. Overview of Glutamatergic Dysregulation in Central Pathologies. Biomolecules 2015; 5:3112-41. [PMID: 26569330 PMCID: PMC4693272 DOI: 10.3390/biom5043112] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 12/27/2022] Open
Abstract
As the major excitatory neurotransmitter in the mammalian central nervous system, glutamate plays a key role in many central pathologies, including gliomas, psychiatric, neurodevelopmental, and neurodegenerative disorders. Post-mortem and serological studies have implicated glutamatergic dysregulation in these pathologies, and pharmacological modulation of glutamate receptors and transporters has provided further validation for the involvement of glutamate. Furthermore, efforts from genetic, in vitro, and animal studies are actively elucidating the specific glutamatergic mechanisms that contribute to the aetiology of central pathologies. However, details regarding specific mechanisms remain sparse and progress in effectively modulating glutamate to alleviate symptoms or inhibit disease states has been relatively slow. In this report, we review what is currently known about glutamate signalling in central pathologies. We also discuss glutamate's mediating role in comorbidities, specifically cancer-induced bone pain and depression.
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Affiliation(s)
- Tanya Miladinovic
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
| | - Mina G Nashed
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
| | - Gurmit Singh
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
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202
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Huseby NE, Ravuri C, Moens U. The proteasome inhibitor lactacystin enhances GSH synthesis capacity by increased expression of antioxidant components in an Nrf2-independent, but p38 MAPK-dependent manner in rat colorectal carcinoma cells. Free Radic Res 2015; 50:1-13. [PMID: 26530909 DOI: 10.3109/10715762.2015.1100730] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Proteasome inhibitors may induce ER stress and oxidative stress, disrupt signaling pathways, and trigger apoptosis in several cancer cells. However, they are also reported to increase glutathione (GSH) synthesis and protect cells from oxidative stress. In the present study, we showed that the proteasome inhibitor lactacystin increased reactive oxygen species (ROS) and GSH levels after the treatment of HT-29 colorectal cancer cells. The increased GSH depended upon the activity of glutamate cysteine ligase (GCL), uptake of cystine/cysteine via the cystine/glutamate transporter [Formula: see text], and the activity of γ-glutamyltransferase (GGT). Increased transcription levels of the catalytic subunit of glutamate cysteine ligase (GCLC), the catalytic subunit xCT of [Formula: see text], and GGT were induced by lactacystin, although with different kinetics and stoichiometry. Lactacystin treatment also augmented protein levels of GCLC, xCT, and GGT, but significant levels were not detected until 48 h after initiation of lactacystin treatment. These increases in protein levels were dependent on the p38 MAPK pathway. Studies in cells transfected with siRNA against the transcription factor Nrf2 demonstrated that the promoter activities of xCT and GCLC, but not of GGT, depended on Nrf2. However, depletion of Nrf2 had no effect on lactacystin-induced upregulation of the GGT, GCLC, and xCT mRNA levels. Taken together, our results suggest that oxidative stress provoked by proteasomal inhibition results in the elevation of cellular GSH levels due to increased synthesis of GSH and uptake of cystine/cysteine. Following treatment with lactacystin, enhanced expression of antioxidant components involved in GSH homeostasis is p38 MAPK-dependent, but Nrf2-independent, resulting in increased GSH synthesis capacity.
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Affiliation(s)
- Nils-Erik Huseby
- a Tumor Biology Research Group, Department of Medical Biology, Faculty of Health Sciences , University of Tromsø , Tromsø , Norway
| | - Chandra Ravuri
- a Tumor Biology Research Group, Department of Medical Biology, Faculty of Health Sciences , University of Tromsø , Tromsø , Norway
| | - Ugo Moens
- b Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences , University of Tromsø , Tromsø , Norway
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203
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Wen ZH, Chang YC, Jean YH. Excitatory amino acid glutamate: role in peripheral nociceptive transduction and inflammation in experimental and clinical osteoarthritis. Osteoarthritis Cartilage 2015; 23:2009-16. [PMID: 26521747 DOI: 10.1016/j.joca.2015.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/15/2015] [Accepted: 03/18/2015] [Indexed: 02/02/2023]
Abstract
Although a large proportion of patients with osteoarthritis (OA) show inflammation in their affected joints, the pathological role of inflammation in the development and progression of OA has yet to be clarified. Glutamate is considered an excitatory amino acid (EAA) neurotransmitter in the mammalian central nervous system (CNS). There are cellular membrane glutamate receptors and transporters for signal input modulation and termination as well as vesicular glutamate transporters (VGLUTs) for signal output through exocytotic release. Glutamate been shown to mediate intercellular communications in bone cells in a manner similar to synaptic transmission within the CNS. Glutamate-mediated events may also contribute to the pathogenesis and ongoing processes of peripheral nociceptive transduction and inflammation of experimental arthritis models as well as human arthritic conditions. This review will discuss the differential roles of glutamate signaling and blockade in peripheral neuronal and non-neuronal joint tissues, including bone remodeling systems and their potentials to impact OA-related inflammation and progression. This will serve to identify several potential targets to direct novel therapies for OA. Future studies will further elucidate the role of glutamate in the development and progression of OA, as well as its association with the clinical features of the disease.
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Affiliation(s)
- Z-H Wen
- Marine Biomedical Laboratory & Center for Translational Biopharmaceuticals, Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Taiwan
| | - Y-C Chang
- Marine Biomedical Laboratory & Center for Translational Biopharmaceuticals, Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Taiwan
| | - Y-H Jean
- Department of Orthopedic Surgery, Pingtung Christian Hospital, Pingtung, Taiwan.
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204
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Patel D, Kharkar PS, Nandave M. Emerging roles of system antiporter and its inhibition in CNS disorders. Mol Membr Biol 2015; 32:89-116. [PMID: 26508554 DOI: 10.3109/09687688.2015.1096972] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | - Prashant S. Kharkar
- Department of Pharmaceutical Chemistry, SPP School of Pharmacy and Technology Management, SVKM’s NMIMS University, Mumbai, India
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205
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Chae SY, Choi CM, Shim TS, Park Y, Park CS, Lee HS, Lee SJ, Oh SJ, Kim SY, Baek S, Koglin N, Stephens AW, Dinkelborg LM, Moon DH. Exploratory Clinical Investigation of (4S)-4-(3-18F-Fluoropropyl)-L-Glutamate PET of Inflammatory and Infectious Lesions. J Nucl Med 2015; 57:67-9. [PMID: 26471694 DOI: 10.2967/jnumed.115.164020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 10/05/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED We explored system [Formula: see text] transporter activity and the detection of inflammatory or infectious lesions using (4S)-4-(3-(18)F-fluoropropyl)-l-glutamate ((18)F-FSPG) PET. METHODS In 10 patients with various inflammatory or infectious diseases, as many as 5 of the largest lesions were selected as reference lesions. (18)F-FSPG images were assessed visually and quantitatively. Expression levels of xCT, CD44, and surface markers of inflammatory cells were evaluated by immunohistochemistry. RESULTS (18)F-FSPG PET detected all reference lesions. (18)F-FSPG uptake in sarcoidosis was significantly higher than that in nonsarcoidosis. The lesion-to-blood-pool SUV ratio for (18)F-FSPG was comparable to that for (18)F-FDG in sarcoidosis. In nonsarcoidosis, however, it was significantly lower. In 5 patients with available tissue samples, the SUVmax for (18)F-FSPG and CD163 were negatively correlated (ρ = -0.872, P = 0.054). CONCLUSION (18)F-FSPG PET may detect inflammatory lesions when activated macrophages or monocytes are present, such as in sarcoidosis.
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Affiliation(s)
- Sun Young Chae
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Chang-Min Choi
- Department of Pulmonology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Tae Sun Shim
- Department of Pulmonology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yangsoon Park
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Chan-Sik Park
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Hyo Sang Lee
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang Ju Lee
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seung Jun Oh
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seog-Young Kim
- Institute for Innovative Cancer Research, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sora Baek
- Department of Nuclear Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea; and
| | | | | | | | - Dae Hyuk Moon
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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206
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Boutter J, Huang Y, Marovca B, Vonderheit A, Grotzer MA, Eckert C, Cario G, Wollscheid B, Horvath P, Bornhauser BC, Bourquin JP. Image-based RNA interference screening reveals an individual dependence of acute lymphoblastic leukemia on stromal cysteine support. Oncotarget 2015; 5:11501-12. [PMID: 25415224 PMCID: PMC4294362 DOI: 10.18632/oncotarget.2572] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/03/2014] [Indexed: 01/22/2023] Open
Abstract
Interactions with the bone marrow microenvironment are essential for leukemia survival and disease progression. We developed an imaging-based RNAi platform to identify protective cues from bone marrow derived mesenchymal stromal cells (MSC) that promote survival of primary acute lymphoblastic leukemia (ALL) cells. Using a candidate gene approach, we detected distinct responses of individual ALL cases to RNA interference with stromal targets. The strongest effects were observed when interfering with solute carrier family 3 member 2 (SLC3A2) expression, which forms the cystine transporter xc− when associated with SLC7A11. Import of cystine and metabolism to cysteine by stromal cells provides the limiting substrate to generate and maintain glutathione in ALL. This metabolic interaction reduces oxidative stress in ALL cells that depend on stromal xc−. Indeed, cysteine depletion using cysteine dioxygenase resulted in leukemia cell death. Thus, functional evaluation of intercellular interactions between leukemia cells and their microenvironment identifies a selective dependency of ALL cells on stromal metabolism for a relevant subgroup of cases, providing new opportunities to develop more personalized approaches to leukemia treatment.
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Affiliation(s)
- Jeannette Boutter
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Yun Huang
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Blerim Marovca
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | | | - Michael A Grotzer
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Cornelia Eckert
- Department of Pediatric Oncology/Hematology, Charité Universitätsmedizin Berlin, Germany
| | - Gunnar Cario
- Department of Pediatrics, University Medical Centre Schleswig-Holstein, Kiel, Germany
| | - Bernd Wollscheid
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Peter Horvath
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, Hungary. Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Beat C Bornhauser
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Jean-Pierre Bourquin
- Department of Pediatric Oncology, University Children's Hospital Zurich, Zurich, Switzerland. Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
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207
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Chen L, Cui H. Targeting Glutamine Induces Apoptosis: A Cancer Therapy Approach. Int J Mol Sci 2015; 16:22830-55. [PMID: 26402672 PMCID: PMC4613338 DOI: 10.3390/ijms160922830] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 09/11/2015] [Accepted: 09/15/2015] [Indexed: 02/06/2023] Open
Abstract
Glutamine metabolism has been proved to be dysregulated in many cancer cells, and is essential for proliferation of most cancer cells, which makes glutamine an appealing target for cancer therapy. In order to be well used by cells, glutamine must be transported to cells by specific transporters and converted to glutamate by glutaminase. There are currently several drugs that target glutaminase under development or clinical trials. Also, glutamine metabolism restriction has been proved to be effective in inhibiting tumor growth both in vivo and vitro through inducing apoptosis, growth arrest and/or autophagy. Here, we review recent researches about glutamine metabolism in cancer, and cell death induced by targeting glutamine, and their potential roles in cancer therapy.
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Affiliation(s)
- Lian Chen
- Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Sichuan Agriculture University, Ya'an 625014, China.
| | - Hengmin Cui
- Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Sichuan Agriculture University, Ya'an 625014, China.
- College of Veterinary Medicine, Sichuan Agricultural University, Ya'an 625014, China.
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208
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Hu H, Takano N, Xiang L, Gilkes DM, Luo W, Semenza GL. Hypoxia-inducible factors enhance glutamate signaling in cancer cells. Oncotarget 2015; 5:8853-68. [PMID: 25326682 PMCID: PMC4253402 DOI: 10.18632/oncotarget.2593] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Signaling through glutamate receptors has been reported in human cancers, but the molecular mechanisms are not fully delineated. We report that in hepatocellular carcinoma and clear cell renal carcinoma cells, increased activity of hypoxia-inducible factors (HIFs) due to hypoxia or VHL loss-of-function, respectively, augmented release of glutamate, which was mediated by HIF-dependent expression of the SLC1A1 and SLC1A3 genes encoding glutamate transporters. In addition, HIFs coordinately regulated expression of the GRIA2 and GRIA3 genes, which encode glutamate receptors. Binding of glutamate to its receptors activated SRC family kinases and downstream pathways, which stimulated cancer cell proliferation, apoptosis resistance, migration and invasion in different cancer cell lines. Thus, coordinate regulation of glutamate transporters and receptors by HIFs was sufficient to activate key signal transduction pathways that promote cancer progression.
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Affiliation(s)
- Hongxia Hu
- Predoctoral Training Program in Human Genetics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Naoharu Takano
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lisha Xiang
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Daniele M Gilkes
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Weibo Luo
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Gregg L Semenza
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
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209
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Thomas AG, Sattler R, Tendyke K, Loiacono KA, Hansen H, Sahni V, Hashizume Y, Rojas C, Slusher BS. High-Throughput Assay Development for Cystine-Glutamate Antiporter (xc-) Highlights Faster Cystine Uptake than Glutamate Release in Glioma Cells. PLoS One 2015; 10:e0127785. [PMID: 26252954 PMCID: PMC4529246 DOI: 10.1371/journal.pone.0127785] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 04/19/2015] [Indexed: 01/22/2023] Open
Abstract
The cystine-glutamate antiporter (system xc-) is a Na+-independent amino acid transporter that exchanges extracellular cystine for intracellular glutamate. It is thought to play a critical role in cellular redox processes through regulation of intracellular glutathione synthesis via cystine uptake. In gliomas, system xc- expression is universally up-regulated while that of glutamate transporters down-regulated, leading to a progressive accumulation of extracellular glutamate and excitotoxic cell death of the surrounding non-tumorous tissue. Additionally, up-regulation of system xc- in activated microglia has been implicated in the pathogenesis of several neurodegenerative disorders mediated by excess glutamate. Consequently, system xc- is a new drug target for brain cancer and neuroinflammatory diseases associated with excess extracellular glutamate. Unfortunately no potent and selective small molecule system xc- inhibitors exist and to our knowledge, no high throughput screening (HTS) assay has been developed to identify new scaffolds for inhibitor design. To develop such an assay, various neuronal and non-neuronal human cells were evaluated as sources of system xc-. Human glioma cells were chosen based on their high system xc- activity. Using these cells, [14C]-cystine uptake and cystine-induced glutamate release assays were characterized and optimized with respect to cystine and protein concentrations and time of incubation. A pilot screen of the LOPAC/NINDS libraries using glutamate release demonstrated that the logistics of the assay were in place but unfortunately, did not yield meaningful pharmacophores. A larger, HTS campaign using the 384-well cystine-induced glutamate release as primary assay and the 96-well 14C-cystine uptake as confirmatory assay is currently underway. Unexpectedly, we observed that the rate of cystine uptake was significantly faster than the rate of glutamate release in human glioma cells. This was in contrast to the same rates of cystine uptake and glutamate release previously reported in normal human fibroblast cells.
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Affiliation(s)
- Ajit G. Thomas
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
| | - Rita Sattler
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
| | - Karen Tendyke
- Next Generation Systems CFU, Eisai Inc., Andover, MA, 01810, United States of America
| | - Kara A. Loiacono
- Next Generation Systems CFU, Eisai Inc., Andover, MA, 01810, United States of America
| | - Hans Hansen
- Next Generation Systems CFU, Eisai Inc., Andover, MA, 01810, United States of America
| | - Vishal Sahni
- Neuroscience and General Medicine PCU, Eisai Inc., Andover, MA, 01810, United States of America
| | - Yutaka Hashizume
- Neuroscience and General Medicine PCU, Eisai Inc., Andover, MA, 01810, United States of America
| | - Camilo Rojas
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- Department of Comparative Medicine and Molecular Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- * E-mail: (CR); (BSS)
| | - Barbara S. Slusher
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States of America
- * E-mail: (CR); (BSS)
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210
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Xc- inhibitor sulfasalazine sensitizes colorectal cancer to cisplatin by a GSH-dependent mechanism. Cancer Lett 2015; 368:88-96. [PMID: 26254540 DOI: 10.1016/j.canlet.2015.07.031] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/22/2015] [Accepted: 07/26/2015] [Indexed: 01/17/2023]
Abstract
Sulfasalazine (SSZ) is an anti-inflammatory drug that has been demonstrated to induce apoptosis and tumor regression through inhibition of plasma membrane cystine transporter xc(-). Cysteine is a rate-limiting precursor for intracellular glutathione (GSH) synthesis, which is vital for compound detoxification and maintaining redox balance. Platinum-based chemotherapy is an important regimen used in clinics for various cancers including colorectal cancer (CRC). We hypothesized that targeting xc(-) transporter by SSZ may annihilate cellular detoxification through interruption of GSH synthesis and may enhance the anti-cancer activity of cisplatin (CDDP) by increasing drug transport. In the present study, we revealed that xCT, the active subunit of xc(-), is highly expressed in CRC cell lines and human colorectal carcinoma tissues compared with their normal counterparts. SSZ effectively depleted cellular GSH, leading to significant accumulation of reactive oxygen species and growth inhibition in CRC cells. In contrast, the normal epithelial cells of colon origin were less sensitive to SSZ, showing a moderate ROS elevation. Importantly, SSZ effectively enhanced the intracellular platinum level and cytotoxicity of CDDP in CRC cells. The synergistic effect of SSZ and CDDP was reversed by antioxidant N-acetyl-L-cysteine (NAC). Together, these results suggest that SSZ, a relatively non-toxic drug that targets cystine transporter, may, in combination with CDDP, have effective therapy for colorectal cancer.
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211
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Zou HM, Zhang B, Xu XC, Su J, Sun YN, Xue S, Wang XY, Qiu MF. Urinary metabolomic strategy to evaluate Compound Danshen Dripping Pills for myocardial ischaemia in rats. J Pharm Biomed Anal 2015; 112:98-105. [DOI: 10.1016/j.jpba.2015.04.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/23/2022]
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Su J, Liu F, Xia M, Xu Y, Li X, Kang J, Li Y, Sun L. p62 participates in the inhibition of NF-κB signaling and apoptosis induced by sulfasalazine in human glioma U251 cells. Oncol Rep 2015; 34:235-43. [PMID: 25937318 DOI: 10.3892/or.2015.3944] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/13/2014] [Indexed: 11/06/2022] Open
Abstract
Nuclear factor-κB (NF-κB) is constitutively activated in most malignant gliomas and is involved in cancer progression and drug resistance to chemotherapy. Sulfasalazine (SAS) is a classic inhibitor of NF-κB. Apoptosis and autophagy were induced by SAS accompanied by inhibition of NF-κB signaling in U251 cells. Inhibition of autophagy by 3-MA suppressed the effects of SAS on NF-κB signaling and apoptosis in U251 cells. Multifunctional scaffold protein p62 is well known as an autophagy marker protein and provides crosstalk for important signaling pathways, including NF-κB signaling. SAS-induced decrease in the p62 protein levels may be the result of degradation through autophagy. SAS induced the inhibition of NF-κB signaling and apoptosis at least partly via a p62-dependent effect in U251 cells. Collectively, our data shed light on the link between p62 and the NF-κB signaling pathway, particularly in glioma cells. The results may facilitate the design of more effective targeted therapies for the treatment of tumors in which NF-κB signaling is altered.
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Affiliation(s)
- Jing Su
- Department of Pathophysiology, Key Laboratory of Pathophysiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Fei Liu
- Department of Nursing, First Hospital, Jilin University, Changchun 130021, P.R. China
| | - Meihui Xia
- Department of Obstetrics, First Hospital, Jilin University, Changchun 130021, P.R. China
| | - Ye Xu
- Medical Research Laboratory, Jilin Medical College, Jilin 132013, P.R. China
| | - Xiaoning Li
- Department of Pathophysiology, Key Laboratory of Pathophysiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Jinsong Kang
- Department of Pathophysiology, Key Laboratory of Pathophysiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Yulin Li
- Department of Pathophysiology, Key Laboratory of Pathophysiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Liankun Sun
- Department of Pathophysiology, Key Laboratory of Pathophysiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
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213
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Abdo N, Xia M, Brown CC, Kosyk O, Huang R, Sakamuru S, Zhou YH, Jack JR, Gallins P, Xia K, Li Y, Chiu WA, Motsinger-Reif AA, Austin CP, Tice RR, Rusyn I, Wright FA. Population-based in vitro hazard and concentration-response assessment of chemicals: the 1000 genomes high-throughput screening study. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:458-66. [PMID: 25622337 PMCID: PMC4421772 DOI: 10.1289/ehp.1408775] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 01/12/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND Understanding of human variation in toxicity to environmental chemicals remains limited, so human health risk assessments still largely rely on a generic 10-fold factor (10½ each for toxicokinetics and toxicodynamics) to account for sensitive individuals or subpopulations. OBJECTIVES We tested a hypothesis that population-wide in vitro cytotoxicity screening can rapidly inform both the magnitude of and molecular causes for interindividual toxicodynamic variability. METHODS We used 1,086 lymphoblastoid cell lines from the 1000 Genomes Project, representing nine populations from five continents, to assess variation in cytotoxic response to 179 chemicals. Analysis included assessments of population variation and heritability, and genome-wide association mapping, with attention to phenotypic relevance to human exposures. RESULTS For about half the tested compounds, cytotoxic response in the 1% most "sensitive" individual occurred at concentrations within a factor of 10½ (i.e., approximately 3) of that in the median individual; however, for some compounds, this factor was > 10. Genetic mapping suggested important roles for variation in membrane and transmembrane genes, with a number of chemicals showing association with SNP rs13120371 in the solute carrier SLC7A11, previously implicated in chemoresistance. CONCLUSIONS This experimental approach fills critical gaps unaddressed by recent large-scale toxicity testing programs, providing quantitative, experimentally based estimates of human toxicodynamic variability, and also testable hypotheses about mechanisms contributing to interindividual variation.
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Affiliation(s)
- Nour Abdo
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Gonzalez Herrera KN, Lee J, Haigis MC. Intersections between mitochondrial sirtuin signaling and tumor cell metabolism. Crit Rev Biochem Mol Biol 2015; 50:242-55. [PMID: 25898275 DOI: 10.3109/10409238.2015.1031879] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cancer cells use glucose and glutamine to facilitate cell growth and proliferation, a process coined "metabolic reprograming" - an emerging hallmark of cancer. Inside the cell, these nutrients synergize to produce metabolic building blocks, such as nucleic acids, lipids and proteins, as well as energy (ATP), glutathione and reducing equivalents (NADPH), required for survival, growth and proliferation. Intense research aimed at understanding the underlying cause of the metabolic rewiring has revealed that established oncogenes and tumor suppressors involved in signaling alter cellular metabolism to contribute to the transition from a normal quiescent cell to a rapidly proliferating cancer cell. Likewise, bona fide metabolic sensors are emerging as regulators of tumorigenesis. This review will focus on one such family of sensors, sirtuins, which utilize NAD(+) as a cofactor to catalyze deacetylation, deacylation and ADP-ribosylation of their protein substrates. In this review, we will enumerate how cancer cell metabolism is different from a normal quiescent cell and highlight the emerging role of mitochondrial sirtuin signaling in the regulation of tumor metabolism.
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Linher-Melville K, Haftchenary S, Gunning P, Singh G. Signal transducer and activator of transcription 3 and 5 regulate system Xc- and redox balance in human breast cancer cells. Mol Cell Biochem 2015; 405:205-21. [DOI: 10.1007/s11010-015-2412-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/09/2015] [Indexed: 12/23/2022]
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216
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Jiang L, Kon N, Li T, Wang SJ, Su T, Hibshoosh H, Baer R, Gu W. Ferroptosis as a p53-mediated activity during tumour suppression. Nature 2015; 520:57-62. [PMID: 25799988 DOI: 10.1038/nature14344] [Citation(s) in RCA: 1909] [Impact Index Per Article: 212.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 02/18/2015] [Indexed: 02/06/2023]
Abstract
Although p53-mediated cell-cycle arrest, senescence and apoptosis serve as critical barriers to cancer development, emerging evidence suggests that the metabolic activities of p53 are also important. Here we show that p53 inhibits cystine uptake and sensitizes cells to ferroptosis, a non-apoptotic form of cell death, by repressing expression of SLC7A11, a key component of the cystine/glutamate antiporter. Notably, p53(3KR), an acetylation-defective mutant that fails to induce cell-cycle arrest, senescence and apoptosis, fully retains the ability to regulate SLC7A11 expression and induce ferroptosis upon reactive oxygen species (ROS)-induced stress. Analysis of mutant mice shows that these non-canonical p53 activities contribute to embryonic development and the lethality associated with loss of Mdm2. Moreover, SLC7A11 is highly expressed in human tumours, and its overexpression inhibits ROS-induced ferroptosis and abrogates p53(3KR)-mediated tumour growth suppression in xenograft models. Our findings uncover a new mode of tumour suppression based on p53 regulation of cystine metabolism, ROS responses and ferroptosis.
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Affiliation(s)
- Le Jiang
- Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Ning Kon
- Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Tongyuan Li
- Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Shang-Jui Wang
- Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Tao Su
- 1] Department of Pathology and Cell Biology, College of Physicians &Surgeons, Columbia University 630 West 168th Street, New York, New York 10032, USA [2] Herbert Irving Comprehensive Cancer Center, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Hanina Hibshoosh
- 1] Department of Pathology and Cell Biology, College of Physicians &Surgeons, Columbia University 630 West 168th Street, New York, New York 10032, USA [2] Herbert Irving Comprehensive Cancer Center, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Richard Baer
- 1] Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA [2] Department of Pathology and Cell Biology, College of Physicians &Surgeons, Columbia University 630 West 168th Street, New York, New York 10032, USA [3] Herbert Irving Comprehensive Cancer Center, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
| | - Wei Gu
- 1] Institute for Cancer Genetics, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA [2] Department of Pathology and Cell Biology, College of Physicians &Surgeons, Columbia University 630 West 168th Street, New York, New York 10032, USA [3] Herbert Irving Comprehensive Cancer Center, College of Physicians &Surgeons, Columbia University 1130 St Nicholas Ave, New York, New York 10032, USA
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Kobayashi S, Sato M, Kasakoshi T, Tsutsui T, Sugimoto M, Osaki M, Okada F, Igarashi K, Hiratake J, Homma T, Conrad M, Fujii J, Soga T, Bannai S, Sato H. Cystathionine is a novel substrate of cystine/glutamate transporter: implications for immune function. J Biol Chem 2015; 290:8778-88. [PMID: 25713140 DOI: 10.1074/jbc.m114.625053] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Indexed: 01/20/2023] Open
Abstract
The cystine/glutamate transporter, designated as system xc(-), is important for maintaining intracellular glutathione levels and extracellular redox balance. The substrate-specific component of system xc(-), xCT, is strongly induced by various stimuli, including oxidative stress, whereas it is constitutively expressed only in specific brain regions and immune tissues, such as the thymus and spleen. Although cystine and glutamate are the well established substrates of system xc(-) and the knockout of xCT leads to alterations of extracellular redox balance, nothing is known about other potential substrates. We thus performed a comparative metabolite analysis of tissues from xCT-deficient and wild-type mice using capillary electrophoresis time-of-flight mass spectrometry. Although most of the analyzed metabolites did not show significant alterations between xCT-deficient and wild-type mice, cystathionine emerged as being absent specifically in the thymus and spleen of xCT-deficient mice. No expression of either cystathionine β-synthase or cystathionine γ-lyase was observed in the thymus and spleen of mice. In embryonic fibroblasts derived from wild-type embryos, cystine uptake was significantly inhibited by cystathionine in a concentration-dependent manner. Wild-type cells showed an intracellular accumulation of cystathionine when incubated in cystathionine-containing buffer, which concomitantly stimulated an increased release of glutamate into the extracellular space. By contrast, none of these effects could be observed in xCT-deficient cells. Remarkably, unlike knock-out cells, wild-type cells could be rescued from cystine deprivation-induced cell death by cystathionine supplementation. We thus conclude that cystathionine is a novel physiological substrate of system xc(-) and that the accumulation of cystathionine in immune tissues is exclusively mediated by system xc(-).
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Affiliation(s)
- Sho Kobayashi
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan, the Department of Functional Genomics and Biotechnology, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan, the Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Mami Sato
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan
| | - Takayuki Kasakoshi
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan
| | - Takumi Tsutsui
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan
| | - Masahiro Sugimoto
- the Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0052, Japan
| | - Mitsuhiko Osaki
- the Division of Pathological Biochemistry, Tottori University Faculty of Medicine, Yonago 683-8503, Japan, the Chromosome Engineering Research Center, Tottori University, Yonago, 683-8503, Japan
| | - Futoshi Okada
- the Division of Pathological Biochemistry, Tottori University Faculty of Medicine, Yonago 683-8503, Japan, the Chromosome Engineering Research Center, Tottori University, Yonago, 683-8503, Japan
| | - Kiharu Igarashi
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan
| | - Jun Hiratake
- the Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Takujiro Homma
- the Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan, and
| | - Marcus Conrad
- the Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Junichi Fujii
- the Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan, and
| | - Tomoyoshi Soga
- the Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0052, Japan
| | - Shiro Bannai
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan
| | - Hideyo Sato
- From the Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555, Japan, the Department of Functional Genomics and Biotechnology, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan, the Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Faculty of Medicine, Niigata University, Chuo-ku, Niigata 951-8518, Japan
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Dai L, Noverr MC, Parsons C, Kaleeba JAR, Qin Z. xCT, not just an amino-acid transporter: a multi-functional regulator of microbial infection and associated diseases. Front Microbiol 2015; 6:120. [PMID: 25745420 PMCID: PMC4333839 DOI: 10.3389/fmicb.2015.00120] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/30/2015] [Indexed: 12/23/2022] Open
Abstract
Expression of xCT, a component of the xc– amino-acid transporter, is essential for the uptake of cystine required for intracellular glutathione (GSH) synthesis and maintenance of the intracellular redox balance. Therefore, xCT plays an important role not only in the survival of somatic and immune cells, but also in other aspects of tumorigenesis, including the growth and malignant progression of cancer cells, resistance to anticancer drugs, and protection of normal cells against oxidative damage induced by carcinogens. xCT also functions as a factor required for infection by Kaposi’s sarcoma-associated herpesvirus (KSHV), the causative agent of Kaposi’s sarcoma (KS) and other lymphoproliferative diseases associated with HIV/AIDS. In spite of these advances, our understanding of the role of xCT in the pathogenesis of infectious diseases is still limited. Therefore, this review will summarize recent findings about the functions of xCT in diseases associated with microbial (bacterial or viral) infections, in particular KSHV-associated malignancies. We will also discuss the remaining questions, future directions, as well as evidence that supports the potential benefits of exploring system xc– as a target for prevention and clinical management of microbial diseases and cancer.
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Affiliation(s)
- Lu Dai
- Research Center for Translational Medicine and Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine , Shanghai, China ; Department of Medicine, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center , New Orleans, LA, USA
| | - Mairi C Noverr
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center , New Orleans, LA, USA
| | - Chris Parsons
- Department of Medicine, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center , New Orleans, LA, USA
| | - Johnan A R Kaleeba
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences , Bethesda, MD, USA
| | - Zhiqiang Qin
- Research Center for Translational Medicine and Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine , Shanghai, China ; Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center , New Orleans, LA, USA
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Guo G, Gao F. CXCR3: latest evidence for the involvement of chemokine signaling in bone cancer pain. Exp Neurol 2015; 265:176-9. [PMID: 25681573 DOI: 10.1016/j.expneurol.2015.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 01/22/2015] [Accepted: 02/05/2015] [Indexed: 11/26/2022]
Abstract
Growing evidence indicates that chemokines participate in the generation and maintenance of bone cancer pain (BCP). Recent work in Exp Neurol by Guan et al. (2015) demonstrated the involvement of spinal chemokine receptor CXCR3 and its downstream PI3K/Akt and Raf/MEK/ERK signaling pathways in BCP. This work provides new evidence to support that chemokines participate in central sensitization in BCP condition. Reviewed evidence suggests that few chemokines have been proved to be related to cancer pain. The underlying relationship between CXCR3 signaling and BCP condition requires further study.
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Affiliation(s)
- Genhua Guo
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan 430030, PR China
| | - Feng Gao
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan 430030, PR China.
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Kanno H, Kawakami Z, Mizoguchi K, Ikarashi Y, Kase Y. Yokukansan, a kampo medicine, protects PC12 cells from glutamate-induced death by augmenting gene expression of cystine/glutamate antiporter system Xc-. PLoS One 2014; 9:e116275. [PMID: 25551766 PMCID: PMC4281137 DOI: 10.1371/journal.pone.0116275] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/25/2014] [Indexed: 02/07/2023] Open
Abstract
Effects of the kampo medicine yokukansan on gene expression of the cystine/glutamate antiporter system Xc-, which protects against glutamate-induced cytotoxicity, were examined in Pheochromocytoma cells (PC12 cells). Yokukansan inhibited glutamate-induced PC12 cell death. Similar cytoprotective effects were found in Uncaria hook. Experiments to clarify the active compounds revealed that geissoschizine methyl ether, hirsuteine, hirsutine, and procyanidin B1 in Uncaria hook, had cytoprotective effects. These components enhanced gene expressions of system Xc- subunits xCT and 4F2hc, and also ameliorated the glutamate-induced decrease in glutathione levels. These results suggest that the cytoprotective effect of yokukansan may be attributed to geissoschizine methyl ether, hirsuteine, hirsutine, and procyanidin B1 in Uncaria hook.
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Affiliation(s)
- Hitomi Kanno
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., Inashiki, Ibaraki, Japan
| | - Zenji Kawakami
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., Inashiki, Ibaraki, Japan
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., Inashiki, Ibaraki, Japan
| | - Yasushi Ikarashi
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., Inashiki, Ibaraki, Japan
| | - Yoshio Kase
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., Inashiki, Ibaraki, Japan
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221
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Kaposi's sarcoma-associated herpesvirus induces Nrf2 activation in latently infected endothelial cells through SQSTM1 phosphorylation and interaction with polyubiquitinated Keap1. J Virol 2014; 89:2268-86. [PMID: 25505069 DOI: 10.1128/jvi.02742-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Nuclear factor erythroid 2-related factor 2 (Nrf2), the cellular master regulator of the antioxidant response, dissociates from its inhibitor Keap1 when activated by stress signals and participates in the pathogenesis of viral infections and tumorigenesis. Early during de novo infection of endothelial cells, KSHV induces Nrf2 through an intricate mechanism involving reactive oxygen species (ROS) and prostaglandin E2 (PGE2). When we investigated the Nrf2 activity during latent KSHV infection, we observed increased nuclear serine-40-phosphorylated Nrf2 in human KS lesions compared to that in healthy tissues. Using KSHV long-term-infected endothelial cells (LTC) as a cellular model for KS, we demonstrated that KSHV infection induces Nrf2 constitutively by extending its half-life, increasing its phosphorylation by protein kinase Cζ (PKCζ) via the infection-induced cyclooxygenase-2 (COX-2)/PGE2 axis and inducing its nuclear localization. Nrf2 knockdown in LTC decreased expression of antioxidant genes and genes involved in KS pathogenesis such as the NAD(P)H quinone oxidase 1 (NQO1), gamma glutamylcysteine synthase heavy unit (γGCSH), the cysteine transporter (xCT), interleukin 6 (IL-6), and vascular endothelial growth factor A (VEGF-A) genes. Nrf2 activation was independent of oxidative stress but dependent on the autophagic protein sequestosome-1 (SQSTM1; p62). SQSTM1 levels were elevated in LTC, a consequence of protein accumulation due to decreased autophagy and Nrf2-mediated transcriptional activation. SQSTM1 was phosphorylated on serine-351 and -403, while Keap1 was polyubiquitinated with lysine-63-ubiquitin chains, modifications known to increase their mutual affinity and interaction, leading to Keap1 degradation and Nrf2 activation. The latent KSHV protein Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein (vFLIP) increased SQSTM1 expression and activated Nrf2. Collectively, these results demonstrate that KSHV induces SQSTM1 to constitutively activate Nrf2, which is involved in the regulation of genes participating in KSHV oncogenesis. IMPORTANCE The transcription factor Nrf2 is activated by stress signals, including viral infection, and responds by activating the transcription of cytoprotective genes. Recently, Nrf2 has been implicated in oncogenesis and was shown to be activated during de novo KSHV infection of endothelial cells through ROS-dependent pathways. The present study was undertaken to determine the mechanism of Nrf2 activation during prolonged latent infection of endothelial cells, using an endothelial cell line latently infected with KSHV. We show that Nrf2 activation was elevated in KSHV latently infected endothelial cells independently of oxidative stress but dependent on the autophagic protein sequestosome-1 (SQSTM1), which was involved in the degradation of the Nrf2 inhibitor Keap1. Furthermore, our results indicated that the KSHV latent protein vFLIP participates in Nrf2 activation. This study suggests that KSHV hijacks the host's autophagic protein SQSTM1 to induce Nrf2 activation, thereby manipulating the infected host gene regulation to promote KS pathogenesis.
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Lutgen V, Resch J, Qualmann K, Raddatz NJ, Panhans C, Olander EM, Kong L, Choi S, Mantsch JR, Baker DA. Behavioral assessment of acute inhibition of system xc (-) in rats. Psychopharmacology (Berl) 2014; 231:4637-47. [PMID: 24828877 PMCID: PMC4474164 DOI: 10.1007/s00213-014-3612-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 05/01/2014] [Indexed: 12/20/2022]
Abstract
RATIONALE Gaps in our understanding of glutamatergic signaling may be key obstacles in accurately modeling complex CNS diseases. System xc (-) is an example of a poorly understood component of glutamate homeostasis that has the potential to contribute to CNS diseases. OBJECTIVES This study aims to determine whether system xc (-) contributes to behaviors used to model features of CNS disease states. METHODS In situ hybridization was used to map mRNA expression of xCT throughout the brain. Microdialysis in the prefrontal cortex was used to sample extracellular glutamate levels; HPLC was used to measure extracellular glutamate and tissue glutathione concentrations. Acute administration of sulfasalazine (8-16 mg/kg, IP) was used to decrease system xc (-) activity. Behavior was measured using attentional set shifting, elevated plus maze, open-field maze, Porsolt swim test, and social interaction paradigm. RESULTS The expression of xCT mRNA was detected throughout the brain, with high expression in several structures including the basolateral amygdala and prefrontal cortex. Doses of sulfasalazine that produced a reduction in extracellular glutamate levels were identified and subsequently used in the behavioral experiments. Sulfasalazine impaired performance in attentional set shifting and reduced the amount of time spent in an open arm of an elevated plus maze and the center of an open-field maze without altering behavior in a Porsolt swim test, total distance moved in an open-field maze, or social interaction. CONCLUSIONS The widespread distribution of system xc (-) and involvement in a growing list of behaviors suggests that this form of nonvesicular glutamate release is a key component of excitatory signaling.
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Affiliation(s)
- Victoria Lutgen
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Jon Resch
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Krista Qualmann
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Nicholas J. Raddatz
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Cristina Panhans
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Ellen M. Olander
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - Linghai Kong
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - SuJean Choi
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - John R. Mantsch
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
| | - David A. Baker
- Department of Biomedical Sciences, Marquette University, Suite 446, 561 N. 15 St, Milwaukee, WI 53233
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223
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Bhutia YD, Babu E, Prasad PD, Ganapathy V. The amino acid transporter SLC6A14 in cancer and its potential use in chemotherapy. Asian J Pharm Sci 2014. [DOI: 10.1016/j.ajps.2014.04.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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224
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Ching J, Amiridis S, Stylli SS, Morokoff AP, O'Brien TJ, Kaye AH. A novel treatment strategy for glioblastoma multiforme and glioma associated seizures: increasing glutamate uptake with PPARγ agonists. J Clin Neurosci 2014; 22:21-8. [PMID: 25439749 DOI: 10.1016/j.jocn.2014.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/30/2014] [Accepted: 09/02/2014] [Indexed: 12/14/2022]
Abstract
The established role of glutamate in the pathogenesis of glioma-associated seizures (GAS) led us to investigate a novel treatment method using an established drug class, peroxisome proliferator activated receptor (PPAR) gamma agonists. Previously, sulfasalazine has been shown to prevent release of glutamate from glioma cells and prevent GAS in rodent models. However, raising protein mediated glutamate transport via excitatory amino acid transporter 2 (EAAT2) has not been investigated previously to our knowledge. PPAR gamma agonists are known to upregulate functional EAAT2 expression in astrocytes and prevent excitotoxicity caused by glutamate excess. These agents are also known to have anti-neoplastic mechanisms. Herein we discuss and review the potential mechanisms of these drugs and highlight a novel potential treatment for GAS.
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Affiliation(s)
- Jared Ching
- Department of Surgery, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK.
| | - Stephanie Amiridis
- Department of Surgery, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia
| | - Stanley S Stylli
- Department of Surgery, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Department of Neurosurgery, The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Andrew P Morokoff
- Department of Surgery, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Department of Neurosurgery, The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Terence J O'Brien
- Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia
| | - Andrew H Kaye
- Department of Surgery, The University of Melbourne, Royal Melbourne Hospital, VIC, Australia; Department of Neurosurgery, The Royal Melbourne Hospital, Parkville, VIC, Australia
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225
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Martin L, Gardner LB. Stress-induced inhibition of nonsense-mediated RNA decay regulates intracellular cystine transport and intracellular glutathione through regulation of the cystine/glutamate exchanger SLC7A11. Oncogene 2014; 34:4211-8. [PMID: 25399695 PMCID: PMC4433865 DOI: 10.1038/onc.2014.352] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/18/2014] [Accepted: 09/11/2014] [Indexed: 12/18/2022]
Abstract
SLC7A11 encodes a subunit of the xCT cystine/glutamate amino acid transport system and plays a critical role in the generation of glutathione and the protection of cells from oxidative stress. Expression of SLC7A11 promotes tumorigenesis and chemotherapy resistance, but while SLC7A11 has been previously noted to be upregulated in hypoxic cells its regulation has not been fully delineated. We have recently shown that nonsense mediated RNA decay (NMD) is inhibited by cellular stresses generated by the tumor microenvironment, including hypoxia, and augments tumorigenesis. Here we demonstrate that the inhibition of NMD by various cellular stresses leads to the stabilization and upregulation of SLC7A11 mRNA and protein. The inhibition of NMD and upregulation of SLC7A11 augments intracellular cystine transport, and increases intracellular levels of cysteine and glutathione. Accordinglyy, the inhibition of NMD protects cells against oxidative stress via SLC7A11 upregulation. Together our studies identify a mechanism for the dynamic regulation of SLC7A11, through the stress-inhibited regulation of NMD, and add to the growing evidence that the inhibition of NMD is an adaptive response.
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Affiliation(s)
- L Martin
- Department of Medicine, New York University School of Medicine, New York, NY, USA
| | - L B Gardner
- 1] Department of Medicine, New York University School of Medicine, New York, NY, USA [2] Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA [3] NYU Perlmutter Cancer Center, New York University School of Medicine, New York, NY, USA
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Lachaier E, Louandre C, Ezzoukhry Z, Godin C, Mazière JC, Chauffert B, Galmiche A. La ferroptose, une nouvelle forme de mort cellulaire applicable au traitement médical des cancers. Med Sci (Paris) 2014; 30:779-83. [DOI: 10.1051/medsci/20143008016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Soria FN, Pérez-Samartín A, Martin A, Gona KB, Llop J, Szczupak B, Chara JC, Matute C, Domercq M. Extrasynaptic glutamate release through cystine/glutamate antiporter contributes to ischemic damage. J Clin Invest 2014; 124:3645-55. [PMID: 25036707 DOI: 10.1172/jci71886] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 05/21/2014] [Indexed: 01/21/2023] Open
Abstract
During brain ischemia, an excessive release of glutamate triggers neuronal death through the overactivation of NMDA receptors (NMDARs); however, the underlying pathways that alter glutamate homeostasis and whether synaptic or extrasynaptic sites are responsible for excess glutamate remain controversial. Here, we monitored ischemia-gated currents in pyramidal cortical neurons in brain slices from rodents in response to oxygen and glucose deprivation (OGD) as a real-time glutamate sensor to identify the source of glutamate release and determined the extent of neuronal damage. Blockade of excitatory amino acid transporters or vesicular glutamate release did not inhibit ischemia-gated currents or neuronal damage after OGD. In contrast, pharmacological inhibition of the cystine/glutamate antiporter dramatically attenuated ischemia-gated currents and cell death after OGD. Compared with control animals, mice lacking a functional cystine/glutamate antiporter exhibited reduced anoxic depolarization and neuronal death in response to OGD. Furthermore, glutamate released by the cystine/glutamate antiporter activated extrasynaptic, but not synaptic, NMDARs, and blockade of extrasynaptic NMDARs reduced ischemia-gated currents and cell damage after OGD. Finally, PET imaging showed increased cystine/glutamate antiporter function in ischemic rats. Altogether, these data suggest that cystine/glutamate antiporter function is increased in ischemia, contributing to elevated extracellular glutamate concentration, overactivation of extrasynaptic NMDARs, and ischemic neuronal death.
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228
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Nrf2- and ATF4-dependent upregulation of xCT modulates the sensitivity of T24 bladder carcinoma cells to proteasome inhibition. Mol Cell Biol 2014; 34:3421-34. [PMID: 25002527 DOI: 10.1128/mcb.00221-14] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ubiquitin-proteasome pathway degrades ubiquitinated proteins to remove damaged or misfolded protein and thus plays an important role in the maintenance of many important cellular processes. Because the pathway is also crucial for tumor cell growth and survival, proteasome inhibition by specific inhibitors exhibits potent antitumor effects in many cancer cells. xCT, a subunit of the cystine antiporter system xc (-), plays an important role in cellular cysteine and glutathione homeostasis. Several recent reports have revealed that xCT is involved in cancer cell survival; however, it was unknown whether xCT affects the cytotoxic effects of proteasome inhibitors. In this study, we found that two stress-inducible transcription factors, Nrf2 and ATF4, were upregulated by proteasome inhibition and cooperatively enhance human xCT gene expression upon proteasome inhibition. In addition, we demonstrated that the knockdown of xCT by small interfering RNA (siRNA) or pharmacological inhibition of xCT by sulfasalazine (SASP) or (S)-4-carboxyphenylglycine (CPG) significantly increased the sensitivity of T24 cells to proteasome inhibition. These results suggest that the simultaneous inhibition of both the proteasome and xCT could have therapeutic benefits in the treatment of bladder tumors.
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229
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Zhang W, Xiao H, Parkin KL. Apoptosis in MCF-7 breast cancer cells induced by S-alkenylmercaptocysteine (CySSR) species derived from Allium tissues in combination with sodium selenite. Food Chem Toxicol 2014; 68:1-10. [DOI: 10.1016/j.fct.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/27/2014] [Accepted: 03/01/2014] [Indexed: 12/26/2022]
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xCT, component of cysteine/glutamate transporter, as an independent prognostic factor in human esophageal squamous cell carcinoma. J Gastroenterol 2014; 49:853-63. [PMID: 23771433 DOI: 10.1007/s00535-013-0847-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 05/31/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND xCT is a component of the cysteine/glutamate transporter, which plays a key role in glutathione synthesis. The objectives of the present study were to investigate the role of xCT in the regulation of genes involved in cell cycle progression and the clinicopathological significance of its expression in esophageal squamous cell carcinoma (ESCC). METHODS xCT expression in human ESCC cell lines was analyzed by Western blotting and immunofluorescent staining. Knockdown experiments were conducted with xCT siRNA, and the effect on cell cycle was analyzed. The cells' gene expression profiles were analyzed by microarray analysis. An immunohistochemical analysis of 70 primary tumor samples obtained from ESCC patients that had undergone esophagectomy was performed. RESULTS xCT was highly expressed in TE13 and KYSE170 cells. In these cells, the knockdown of xCT using siRNA inhibited G1-S phase progression. Microarray analysis identified 1652 genes whose expression levels in TE13 cells were altered by the knockdown of xCT. Pathway analysis showed that the top-ranked canonical pathway was the G1/S checkpoint regulation pathway, which involves TP53INP1, CDKN1A, CyclinD1/cdk4, and E2F5. Immunohistochemical staining showed that xCT is mainly found in the nuclei of carcinoma cells, and that its expression is an independent prognostic factor. CONCLUSIONS These observations suggest that the expression of xCT in ESCC cells might affect the G1/S checkpoint and impact on the prognosis of ESCC patients. As a result, we have a deeper understanding of the role played by xCT as a mediator and/or biomarker in ESCC.
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231
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Sugiyama K, Ebinuma H, Nakamoto N, Sakasegawa N, Murakami Y, Chu PS, Usui S, Ishibashi Y, Wakayama Y, Taniki N, Murata H, Saito Y, Fukasawa M, Saito K, Yamagishi Y, Wakita T, Takaku H, Hibi T, Saito H, Kanai T. Prominent steatosis with hypermetabolism of the cell line permissive for years of infection with hepatitis C virus. PLoS One 2014; 9:e94460. [PMID: 24718268 PMCID: PMC3981821 DOI: 10.1371/journal.pone.0094460] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 03/16/2014] [Indexed: 12/11/2022] Open
Abstract
Most of experiments for HCV infection have been done using lytic infection systems, in which HCV-infected cells inevitably die. Here, to elucidate metabolic alteration in HCV-infected cells in a more stable condition, we established an HCV-persistently-infected cell line, designated as HPI cells. This cell line has displayed prominent steatosis and supported HCV infection for more than 2 years, which is the longest ever reported. It enabled us to analyze metabolism in the HCV-infected cells integrally combining metabolomics and expression arrays. It revealed that rate-limiting enzymes for biosynthesis of cholesterol and fatty acids were up-regulated with actual increase in cholesterol, desmosterol (cholesterol precursor) and pool of fatty acids. Notably, the pentose phosphate pathway was facilitated with marked up-regulation of glucose-6-phosphate dehydrogenase, a rete-limiting enzyme, with actual increase in NADPH. In its downstream, enzymes for purine synthesis were also up-regulated resulting in increase of purine. Contrary to common cancers, the TCA cycle was preferentially facilitated comparing to glycolysis pathway with a marked increase of most of amino acids. Interestingly, some genes controlled by nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a master regulator of antioxidation and metabolism, were constitutively up-regulated in HPI cells. Knockdown of Nrf2 markedly reduced steatosis and HCV infection, indicating that Nrf2 and its target genes play important roles in metabolic alteration and HCV infection. In conclusion, HPI cell is a bona fide HCV-persistently-infected cell line supporting HCV infection for years. This cell line sustained prominent steatosis in a hypermetabolic status producing various metabolites. Therefore, HPI cell is a potent research tool not only for persistent HCV infection but also for liver metabolism, overcoming drawbacks of the lytic infection systems.
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Affiliation(s)
- Kazuo Sugiyama
- Center for the Study of Chronic Liver Diseases, Keio University School of Medicine, Tokyo, Japan
- * E-mail:
| | - Hirotoshi Ebinuma
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Nobuhiro Nakamoto
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | | | - Yuko Murakami
- Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Po-sung Chu
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Shingo Usui
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yuka Ishibashi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yuko Wakayama
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Nobuhito Taniki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Hiroko Murata
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yoshimasa Saito
- Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Masayoshi Fukasawa
- Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo, Japan
| | - Kyoko Saito
- Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo, Japan
| | - Yoshiyuki Yamagishi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Takaji Wakita
- Virology II, National Institute of Infectious Disease, Tokyo, Japan
| | - Hiroshi Takaku
- Department of Life and Environmental Sciences, Chiba Institute of Technology, Chiba, Japan
| | - Toshifumi Hibi
- Center for Advanced IBD Research and Treatment, Kitasato Institute Hospital, Kitasato University, Tokyo, Japan
| | - Hidetsugu Saito
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
- Division of Pharmacotherapeutics, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Takanori Kanai
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
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232
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Mifsud G, Zammit C, Muscat R, Di Giovanni G, Valentino M. Oligodendrocyte pathophysiology and treatment strategies in cerebral ischemia. CNS Neurosci Ther 2014; 20:603-12. [PMID: 24703424 DOI: 10.1111/cns.12263] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 12/19/2022] Open
Abstract
Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, form a functional unit with axons and play a crucial role in axonal integrity. An episode of hypoxia-ischemia causes rapid and severe damage to these particularly vulnerable cells via multiple pathways such as overactivation of glutamate and ATP receptors, oxidative stress, and disruption of mitochondrial function. The cardinal effect of OL pathology is demyelination and dysmyelination, and this has profound effects on axonal function, transport, structure, metabolism, and survival. The OL is a primary target of ischemia in adult-onset stroke and especially in periventricular leukomalacia and should be considered as a primary therapeutic target in these conditions. More emphasis is needed on therapeutic strategies that target OLs, myelin, and their receptors, as these have the potential to significantly attenuate white matter injury and to establish functional recovery of white matter after stroke. In this review, we will summarize recent progress on the role of OLs in white matter ischemic injury and the current and emerging principles that form the basis for protective strategies against OL death.
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Affiliation(s)
- Gabriella Mifsud
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
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Abstract
The metabolic adaptations that support oncogenic growth can also render cancer cells dependent on certain nutrients. Along with the Warburg effect, increased utilization of glutamine is one of the metabolic hallmarks of the transformed state. Glutamine catabolism is positively regulated by multiple oncogenic signals, including those transmitted by the Rho family of GTPases and by c-Myc. The recent identification of mechanistically distinct inhibitors of glutaminase, which can selectively block cellular transformation, has revived interest in the possibility of targeting glutamine metabolism in cancer therapy. Here, we outline the regulation and roles of glutamine metabolism within cancer cells and discuss possible strategies for, and the consequences of, impacting these processes therapeutically.
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234
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Yang Y, Yee D. IGF-I regulates redox status in breast cancer cells by activating the amino acid transport molecule xC-. Cancer Res 2014; 74:2295-305. [PMID: 24686172 DOI: 10.1158/0008-5472.can-13-1803] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Insulin-like growth factors (IGF) stimulate cell growth in part by increasing amino acid uptake. xCT (SLC7A11) encodes the functional subunit of the cell surface transport system xC(-), which mediates cystine uptake, a pivotal step in glutathione synthesis and cellular redox control. In this study, we show that IGF-I regulates cystine uptake and cellular redox status by activating the expression and function of xCT in estrogen receptor-positive (ER(+)) breast cancer cells by a mechanism that relies on the IGF receptor substrate-1 (IRS-1). Breast cancer cell proliferation mediated by IGF-I was suppressed by attenuating xCT expression or blocking xCT activity with the pharmacologic inhibitor sulfasalazine (SASP). Notably, SASP sensitized breast cancer cells to inhibitors of the type I IGF receptor (IGF-IR) in a manner reversed by the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine. Thus, IGF-I promoted the proliferation of ER(+) breast cancer cells by regulating xC(-) transporter function to protect cancer cells from ROS in an IRS-1-dependent manner. Our findings suggest that inhibiting xC(-) transporter function may synergize with modalities that target the IGF-IR to heighten their therapeutic effects.
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Affiliation(s)
- Yuzhe Yang
- Authors' Affiliations: Masonic Cancer Center; and Departments of Pharmacology and Medicine, University of Minnesota, Minneapolis, Minnesota
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235
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Sahoo S, Aurich MK, Jonsson JJ, Thiele I. Membrane transporters in a human genome-scale metabolic knowledgebase and their implications for disease. Front Physiol 2014; 5:91. [PMID: 24653705 PMCID: PMC3949408 DOI: 10.3389/fphys.2014.00091] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 02/17/2014] [Indexed: 01/18/2023] Open
Abstract
Membrane transporters enable efficient cellular metabolism, aid in nutrient sensing, and have been associated with various diseases, such as obesity and cancer. Genome-scale metabolic network reconstructions capture genomic, physiological, and biochemical knowledge of a target organism, along with a detailed representation of the cellular metabolite transport mechanisms. Since the first reconstruction of human metabolism, Recon 1, published in 2007, progress has been made in the field of metabolite transport. Recently, we published an updated reconstruction, Recon 2, which significantly improved the metabolic coverage and functionality. Human metabolic reconstructions have been used to investigate the role of metabolism in disease and to predict biomarkers and drug targets. Given the importance of cellular transport systems in understanding human metabolism in health and disease, we analyzed the coverage of transport systems for various metabolite classes in Recon 2. We will review the current knowledge on transporters (i.e., their preferred substrates, transport mechanisms, metabolic relevance, and disease association for each metabolite class). We will assess missing coverage and propose modifications and additions through a transport module that is functional when combined with Recon 2. This information will be valuable for further refinements. These data will also provide starting points for further experiments by highlighting areas of incomplete knowledge. This review represents the first comprehensive overview of the transporters involved in central metabolism and their transport mechanisms, thus serving as a compendium of metabolite transporters specific for human metabolic reconstructions.
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Affiliation(s)
- Swagatika Sahoo
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
| | - Maike K Aurich
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
| | - Jon J Jonsson
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Iceland Reykjavik, Iceland ; Department of Genetics and Molecular Medicine, Landspitali, National University Hospital of Iceland Reykjavik, Iceland
| | - Ines Thiele
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
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Webster JM, Morton CA, Johnson BF, Yang H, Rishel MJ, Lee BD, Miao Q, Pabba C, Yapp DT, Schaffer P. Functional imaging of oxidative stress with a novel PET imaging agent, 18F-5-fluoro-L-aminosuberic acid. J Nucl Med 2014; 55:657-64. [PMID: 24578242 DOI: 10.2967/jnumed.113.126664] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED Glutathione is the predominant endogenous cellular antioxidant, playing a critical role in the cellular defensive response to oxidative stress by neutralizing free radicals and reactive oxygen species. With cysteine as the rate-limiting substrate in glutathione biosynthesis, the cystine/glutamate transporter (system xc(-)) represents a potentially attractive PET biomarker to enable in vivo quantification of xc(-) activity in response to oxidative stress associated with disease. We have developed a system xc(-) substrate that incorporates characteristics of both natural substrates, L-cystine and L-glutamate (L-Glu). L-aminosuberic acid (L-ASu) has been identified as a more efficient system xc(-) substrate than L-Glu, leading to an assessment of a series of anionic amino acids as prospective PET tracers. Herein, we report the synthesis and in vitro and in vivo validation of a lead candidate, (18)F-5-fluoro-aminosuberic acid ((18)F-FASu), as a PET tracer for functional imaging of a cellular response to oxidative stress with remarkable tumor uptake and retention. METHODS (18)F-FASu was identified as a potential PET tracer based on an in vitro screening of compounds similar to L-cystine and L-Glu. Affinity toward system xc(-) was determined via in vitro uptake and inhibition studies using oxidative stress-induced EL4 and SKOV-3 cells. In vivo biodistribution and PET imaging studies were performed in mice bearing xenograft tumors (EL4 and SKOV-3). RESULTS In vitro assay results determined that L-ASu inhibited system xc(-) as well as or better than L-Glu. The direct comparison of uptake of tritiated compounds demonstrated more efficient system xc(-) uptake of L-ASu than L-Glu. Radiosynthesis of (18)F-FASu allowed the validation of uptake for the fluorine-bearing derivative in vitro. Evaluation in vivo demonstrated primarily renal clearance and uptake of approximately 8 percentage injected dose per gram in SKOV-3 tumors, with tumor-to-blood and tumor-to-muscle ratios of approximately 12 and approximately 28, respectively. (18)F-FASu uptake was approximately 5 times greater than (18)F-FDG uptake in SKOV-3 tumors. Dynamic PET imaging demonstrated uptake in EL4 tumor xenografts of approximately 6 percentage injected dose per gram and good tumor retention for at least 2 h after injection. CONCLUSION (18)F-FASu is a potentially useful metabolic tracer for PET imaging of a functional cellular response to oxidative stress. (18)F-FASu may provide more sensitive detection than (18)F-FDG in certain tumors.
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Affiliation(s)
- Jack M Webster
- Diagnostics and Biomedical Technologies, GE Global Research, Niskayuna, New York
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237
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Wall BA, Wangari-Talbot J, Shin SS, Schiff D, Sierra J, Yu LJ, Khan A, Haffty B, Goydos JS, Chen S. Disruption of GRM1-mediated signalling using riluzole results in DNA damage in melanoma cells. Pigment Cell Melanoma Res 2014; 27:263-74. [PMID: 24330389 DOI: 10.1111/pcmr.12207] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/26/2013] [Indexed: 12/17/2022]
Abstract
Gain of function of the neuronal receptor, metabotropic glutamate receptor 1 (Grm1), was sufficient to induce melanocytic transformation in vitro and spontaneous melanoma development in vivo when ectopically expressed in melanocytes. The human form of this receptor, GRM1, has been shown to be ectopically expressed in a subset of human melanomas but not benign nevi or normal melanocytes, suggesting that misregulation of GRM1 is involved in the pathogenesis of certain human melanomas. Sustained stimulation of Grm1 by the ligand, glutamate, is required for the maintenance of transformed phenotypes in vitro and tumorigenicity in vivo. In this study, we investigate the mechanism of an inhibitor of glutamate release, riluzole, on human melanoma cells that express metabotropic glutamate receptor 1 (GRM1). Various in vitro assays conducted show that inhibition of glutamate release in several human melanoma cell lines resulted in an increase of oxidative stress and DNA damage response markers.
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Affiliation(s)
- Brian A Wall
- Susan Lehman Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA; Joint Graduate Program of Toxicology, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
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238
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Robert SM, Ogunrinu-Babarinde T, Holt KT, Sontheimer H. Role of glutamate transporters in redox homeostasis of the brain. Neurochem Int 2014; 73:181-91. [PMID: 24418113 DOI: 10.1016/j.neuint.2014.01.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 12/24/2022]
Abstract
Redox homeostasis is especially important in the brain where high oxygen consumption produces an abundance of harmful oxidative by-products. Glutathione (GSH) is a tripeptide non-protein thiol. It is the central nervous system's most abundant antioxidant and the master controller of brain redox homeostasis. The glutamate transporters, System xc(-) (SXC) and the Excitatory Amino Acid Transporters (EAAT), play important, synergistic roles in the synthesis of GSH. In glial cells, SXC mediates the uptake of cystine, which after intracellular reduction to cysteine, reacts with glutamate during the rate-limiting step of GSH synthesis. EAAT3 mediates direct cysteine uptake for neuronal GSH synthesis. SXC and EAAT work in concert in glial cells to provide two intracellular substrates for GSH synthesis, cystine and glutamate. Their cyclical basal function also prevents a buildup of extracellular glutamate, which SXC releases extracellularly in exchange for cystine uptake. Maintaining extracellular glutamate homeostasis is critical to prevent neuronal toxicity, as well as glutamate-mediated SXC inhibition, which could lead to a depletion of intracellular GSH and loss of cellular redox control. Many neurological diseases show evidence of GSH dysfunction, and increased GSH has been widely associated with chemotherapy and radiotherapy resistance of gliomas. We present evidence suggesting that gliomas expressing elevated levels of SXC are more reliant on GSH for growth and survival. They have an increased inherent radiation resistance, however, inhibition of SXC can increase tumor sensitivity at low radiation doses. GSH depletion through SXC inhibition may be a viable mechanism to enhance current glioma treatment strategies and make tumors more sensitive to radiation and chemotherapy protocols.
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Affiliation(s)
- Stephanie M Robert
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, CIRC 425, 1719 6th Ave S, Birmingham, AL 35294, USA.
| | - Toyin Ogunrinu-Babarinde
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, CIRC 425, 1719 6th Ave S, Birmingham, AL 35294, USA
| | - Kenneth T Holt
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, CIRC 425, 1719 6th Ave S, Birmingham, AL 35294, USA
| | - Harald Sontheimer
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, CIRC 425, 1719 6th Ave S, Birmingham, AL 35294, USA.
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TSUKADA RIKA, ISEKI MASAKO. The Latest Clinical Findings for Yokukansan Based on Its Pharmacological Effects: Yokukansan Update. JUNTENDO IJI ZASSHI 2014. [DOI: 10.14789/jmj.60.552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- RIKA TSUKADA
- Department of Anesthesiology and Pain Management, Juntendo University Faculty of Medicine
| | - MASAKO ISEKI
- Department of Anesthesiology and Pain Management, Juntendo University Faculty of Medicine
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240
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Maruo T, Kanemaki N, Onda K, Sato R, Ichihara N, Ochiai H. Canine amino acid transport system Xc(-): cDNA sequence, distribution and cystine transport activity in lens epithelial cells. J Vet Med Sci 2013; 76:523-30. [PMID: 24366150 PMCID: PMC4064136 DOI: 10.1292/jvms.13-0170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cystine transport activity of a lens epithelial cell line originated from a
canine mature cataract was investigated. The distinct cystine transport activity was
observed, which was inhibited to 28% by extracellular 1 mM glutamate. The cDNA sequences
of canine cysteine/glutamate exchanger (xCT) and 4F2hc were determined. The predicted
amino acid sequences were 527 and 533 amino acid polypeptides, respectively. The amino
acid sequences of canine xCT and 4F2hc showed high similarities (>80%) to those of
humans. The expression of xCT in lens epithelial cell line was confirmed by western blot
analysis. RT-PCR analysis revealed high level expression only in the brain, and it was
below the detectable level in other tissues.
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Affiliation(s)
- Takuya Maruo
- Veterinary Teaching Hospital, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuou-ku, Sagamihara, Kanagawa 252-5201, Japan
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241
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Glutamate transporters in the biology of malignant gliomas. Cell Mol Life Sci 2013; 71:1839-54. [PMID: 24281762 DOI: 10.1007/s00018-013-1521-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/22/2013] [Accepted: 11/11/2013] [Indexed: 12/11/2022]
Abstract
Malignant gliomas are relentless tumors that offer a dismal clinical prognosis. They develop many biological advantages that allow them to grow and survive in the unique environment of the brain. The glutamate transporters system x c (-) and excitatory amino acid transporters (EAAT) are emerging as key players in the biology and malignancy of these tumors. Gliomas manipulate glutamate transporter expression and function to alter glutamate homeostasis in the brain, which supports their own growth, invasion, and survival. As a consequence, malignant cells are able to quickly destroy and invade surrounding normal brain. Recent findings are painting a larger picture of these transporters in glioma biology, and as such are providing opportunities for clinical intervention for patients. This review will detail the current understanding of glutamate transporters in the biology of malignant gliomas and highlight some of the unique aspects of these tumors that make them so devastating and difficult to treat.
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242
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Oncogenic alternative splicing switches: role in cancer progression and prospects for therapy. Int J Cell Biol 2013; 2013:962038. [PMID: 24285959 PMCID: PMC3826442 DOI: 10.1155/2013/962038] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/12/2013] [Indexed: 01/30/2023] Open
Abstract
Alterations in the abundance or activities of alternative splicing regulators generate alternatively spliced variants that contribute to multiple aspects of tumor establishment, progression and resistance to therapeutic treatments. Notably, many cancer-associated genes are regulated through alternative splicing suggesting a significant role of this post-transcriptional regulatory mechanism in the production of oncogenes and tumor suppressors. Thus, the study of alternative splicing in cancer might provide a better understanding of the malignant transformation and identify novel pathways that are uniquely relevant to tumorigenesis. Understanding the molecular underpinnings of cancer-associated alternative splicing isoforms will not only help to explain many fundamental hallmarks of cancer, but will also offer unprecedented opportunities to improve the efficacy of anti-cancer treatments.
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243
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Timmerman LA, Holton T, Yuneva M, Louie RJ, Padró M, Daemen A, Hu M, Chan DA, Ethier SP, van 't Veer LJ, Polyak K, McCormick F, Gray JW. Glutamine sensitivity analysis identifies the xCT antiporter as a common triple-negative breast tumor therapeutic target. Cancer Cell 2013; 24:450-65. [PMID: 24094812 PMCID: PMC3931310 DOI: 10.1016/j.ccr.2013.08.020] [Citation(s) in RCA: 420] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 03/21/2013] [Accepted: 08/23/2013] [Indexed: 01/18/2023]
Abstract
A handful of tumor-derived cell lines form the mainstay of cancer therapeutic development, yielding drugs with an impact typically measured as months to disease progression. To develop more effective breast cancer therapeutics and more readily understand their clinical impact, we constructed a functional metabolic portrait of 46 independently derived breast cell lines. Our analysis of glutamine uptake and dependence identified a subset of triple-negative samples that are glutamine auxotrophs. Ambient glutamine indirectly supports environmental cystine acquisition via the xCT antiporter, which is expressed on one-third of triple-negative tumors in vivo. xCT inhibition with the clinically approved anti-inflammatory sulfasalazine decreases tumor growth, revealing a therapeutic target in breast tumors of poorest prognosis and a lead compound for rapid, effective drug development.
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Affiliation(s)
- Luika A Timmerman
- UCSF/Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94115, USA.
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244
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Regenerative glutamate release by presynaptic NMDA receptors contributes to spreading depression. J Cereb Blood Flow Metab 2013; 33:1582-94. [PMID: 23820646 PMCID: PMC3790928 DOI: 10.1038/jcbfm.2013.113] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 11/08/2022]
Abstract
Spreading depression (SD) is a slowly propagating neuronal depolarization that underlies certain neurologic conditions. The wave-like pattern of its propagation suggests that SD arises from an unusual form of neuronal communication. We used enzyme-based glutamate electrodes to show that during SD induced by transiently raising extracellular K(+) concentrations ([K(+)]o) in rat brain slices, there was a rapid increase in the extracellular glutamate concentration that required vesicular exocytosis but unlike fast synaptic transmission, still occurred when voltage-gated sodium and calcium channels (VGSC and VGCC) were blocked. Instead, presynaptic N-methyl-D-aspartate (NMDA) receptors (NMDARs) were activated during SD and could generate substantial glutamate release to support regenerative glutamate release and propagating waves when VGSCs and VGCCs were blocked. In calcium-free solutions, high [K(+)]o still triggered SD-like waves and glutamate efflux. Under such a condition, glutamate release was blocked by mitochondrial Na(+)/Ca(2+) exchanger inhibitors that likely blocked calcium release from mitochondria secondary to NMDA-induced Na(+) influx. Therefore presynaptic NMDA receptor activation is sufficient for triggering vesicular glutamate release during SD via both calcium entry and release from mitochondria by mitochondrial Na(+)/Ca(2+) exchanger. Our observations suggest that presynaptic NMDARs contribute to a cycle of glutamate-induced glutamate release that mediate high [K(+)]o-triggered SD.
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245
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Lozano-Ondoua AN, Symons-Liguori AM, Vanderah TW. Cancer-induced bone pain: Mechanisms and models. Neurosci Lett 2013; 557 Pt A:52-9. [PMID: 24076008 DOI: 10.1016/j.neulet.2013.08.003] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/19/2013] [Accepted: 08/01/2013] [Indexed: 12/13/2022]
Abstract
Cancerous cells can originate in a number of different tissues such as prostate, breast and lung, but often go undetected and are non-painful. Many types of cancers have a propensity to metastasize to the bone microenvironment first. Tumor burden within the bone causes excruciating breakthrough pain with properties of ongoing pain that is inadequately managed with current analgesics. Part of this failure is due to the poor understanding of the etiology of cancer pain. Animal models of cancer-induced bone pain (CIBP) have revealed that the neurochemistry of cancer has features distinctive from other chronic pain states. For example, preclinical models of metastatic cancer often result in the positive modulation of neurotrophins, such as NGF and BDNF, that can lead to nociceptive sensitization. Preclinical cancer models also demonstrate nociceptive neuronal expression of acid-sensing receptors, such as ASIC1 and TRPV1, which respond to cancer-induced acidity within the bone. CIBP is correlated with a significant increase in pro-inflammatory mediators acting peripherally and centrally, contributing to neuronal hypersensitive states. Finally, cancer cells generate high levels of oxidative molecules that are thought to increase extracellular glutamate concentrations, thus activating primary afferent neurons. Knowledge of the unique neuro-molecular profile of cancer pain will ultimately lead to the development of novel and superior therapeutics for CIBP.
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Affiliation(s)
- A N Lozano-Ondoua
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA
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246
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Takeuchi S, Wada K, Toyooka T, Shinomiya N, Shimazaki H, Nakanishi K, Nagatani K, Otani N, Osada H, Uozumi Y, Matsuo H, Nawashiro H. Increased xCT expression correlates with tumor invasion and outcome in patients with glioblastomas. Neurosurgery 2013; 72:33-41; discussion 41. [PMID: 23096413 DOI: 10.1227/neu.0b013e318276b2de] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND xCT is a light chain of the cystine/glutamate antiporter system xc. Glutamate that is released by system xc plays an important role in the infiltration of glioblastoma (GBM) cells. Furthermore, increased glutathione synthesis by system xc may protect tumor cells against oxidative stress induced by radiotherapy and chemotherapy. OBJECTIVE To investigate whether the levels of xCT expression correlated with infiltrative imaging phenotypes on magnetic resonance imaging and outcomes in patients with GBMs. METHODS Forty patients with histologically confirmed primary GBMs were included in the study. Patient charts were retrospectively reviewed for age, sex, Karnofsky Performance Status Scale score, Mini-Mental State Examination score, magnetic resonance imaging features, xCT expression, isocitrate dehydrogenase 1 R132H expression, O-methylguanine-DNA methyltransferase promoter methylation status, type of surgery, progression-free survival, and overall survival. RESULTS In invasive margins, xCT expression was weak in 20 patients and strong in 20 patients. A Cox regression model revealed that a Karnofsky Performance Status Scale score less than 60 (hazard ratio [HR]: 4.525; P = .01), partial removal (HR: 2.839; P = .03), and strong xCT expression (HR: 4.134; P < .001) were significantly associated with shorter progression-free survival and that partial removal (HR: 2.865; P = .03), weak isocitrate dehydrogenase 1 R132H expression (HR: 15.729; P = .01), and strong xCT expression (HR: 2.863; P = .04) were significantly associated with shorter overall survival. CONCLUSION These findings suggest that xCT is an independent predictive factor in GBMs.
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Affiliation(s)
- Satoru Takeuchi
- Department of Neurosurgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
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247
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McCracken AN, Edinger AL. Nutrient transporters: the Achilles' heel of anabolism. Trends Endocrinol Metab 2013; 24:200-8. [PMID: 23402769 PMCID: PMC3617053 DOI: 10.1016/j.tem.2013.01.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 01/08/2023]
Abstract
Highly proliferative cells, including cancer cells, require a constant supply of molecular building blocks to support their growth. To acquire substrates such as glucose and amino acids from the extracellular space, dividing cells rely on transporter proteins in the plasma membrane. Numerous studies link transcriptional and post-translational control of nutrient transporter expression with proliferation, highlighting the importance of nutrient transporters in both physiologic and pathologic growth. Here we review recent work that spotlights the crucial role of nutrient transporters in cell growth and proliferation, discuss post-translational mechanisms for coordinating expression of different transporters, and consider the therapeutic potential of targeting these proteins in cancer and other diseases characterized by inappropriate cell division.
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Affiliation(s)
| | - Aimee L. Edinger
- Corresponding Author: Aimee L. Edinger 2128 Natural Sciences 1 University of California, Irvine Irvine, CA 92697-2300 Tel: 949-824-1921 FAX: 949-824-4709
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248
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Lewerenz J, Hewett SJ, Huang Y, Lambros M, Gout PW, Kalivas PW, Massie A, Smolders I, Methner A, Pergande M, Smith SB, Ganapathy V, Maher P. The cystine/glutamate antiporter system x(c)(-) in health and disease: from molecular mechanisms to novel therapeutic opportunities. Antioxid Redox Signal 2013; 18:522-55. [PMID: 22667998 PMCID: PMC3545354 DOI: 10.1089/ars.2011.4391] [Citation(s) in RCA: 644] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The antiporter system x(c)(-) imports the amino acid cystine, the oxidized form of cysteine, into cells with a 1:1 counter-transport of glutamate. It is composed of a light chain, xCT, and a heavy chain, 4F2 heavy chain (4F2hc), and, thus, belongs to the family of heterodimeric amino acid transporters. Cysteine is the rate-limiting substrate for the important antioxidant glutathione (GSH) and, along with cystine, it also forms a key redox couple on its own. Glutamate is a major neurotransmitter in the central nervous system (CNS). By phylogenetic analysis, we show that system x(c)(-) is a rather evolutionarily new amino acid transport system. In addition, we summarize the current knowledge regarding the molecular mechanisms that regulate system x(c)(-), including the transcriptional regulation of the xCT light chain, posttranscriptional mechanisms, and pharmacological inhibitors of system x(c)(-). Moreover, the roles of system x(c)(-) in regulating GSH levels, the redox state of the extracellular cystine/cysteine redox couple, and extracellular glutamate levels are discussed. In vitro, glutamate-mediated system x(c)(-) inhibition leads to neuronal cell death, a paradigm called oxidative glutamate toxicity, which has successfully been used to identify neuroprotective compounds. In vivo, xCT has a rather restricted expression pattern with the highest levels in the CNS and parts of the immune system. System x(c)(-) is also present in the eye. Moreover, an elevated expression of xCT has been reported in cancer. We highlight the diverse roles of system x(c)(-) in the regulation of the immune response, in various aspects of cancer and in the eye and the CNS.
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Affiliation(s)
- Jan Lewerenz
- Department of Neurology, University of Ulm, Ulm, Germany.
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249
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Nagano O, Okazaki S, Saya H. Redox regulation in stem-like cancer cells by CD44 variant isoforms. Oncogene 2013; 32:5191-8. [PMID: 23334333 DOI: 10.1038/onc.2012.638] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 12/02/2012] [Accepted: 12/03/2012] [Indexed: 12/18/2022]
Abstract
Increasing evidence indicates that several types of solid tumor are hierarchically organized and sustained by a distinct population of cancer stem cells (CSCs). CSCs possess enhanced mechanisms of protection from stress induced by reactive oxygen species (ROS) that render them resistant to chemo- and radiotherapy. Expression of CD44, especially variant isoforms (CD44v) of this major CSC marker, contributes to ROS defense through upregulation of the synthesis of reduced glutathione (GSH), the primary intracellular antioxidant. CD44v interacts with and stabilizes xCT, a subunit of the cystine-glutamate transporter xc(-), and thereby promotes cystine uptake for GSH synthesis. Given that cancer cells are often exposed to high levels of ROS during tumor progression, the ability to avoid the consequences of such exposure is required for cancer cell survival and propagation in vivo. CSCs, in which defense against ROS is enhanced by CD44v are thus thought to drive tumor growth, chemoresistance and metastasis. Therapy targeted to the CD44v-xCT system may therefore impair the ROS defense ability of CSCs and thereby sensitize them to currently available treatments.
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Affiliation(s)
- O Nagano
- Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
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250
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Yoshikawa M, Tsuchihashi K, Ishimoto T, Yae T, Motohara T, Sugihara E, Onishi N, Masuko T, Yoshizawa K, Kawashiri S, Mukai M, Asoda S, Kawana H, Nakagawa T, Saya H, Nagano O. xCT inhibition depletes CD44v-expressing tumor cells that are resistant to EGFR-targeted therapy in head and neck squamous cell carcinoma. Cancer Res 2013; 73:1855-66. [PMID: 23319806 DOI: 10.1158/0008-5472.can-12-3609-t] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The targeting of antioxidant systems that allow stem-like cancer cells to avoid the adverse consequences of oxidative stress might be expected to improve the efficacy of cancer treatment. Here, we show that head and neck squamous cell carcinoma (HNSCC) cells that express variant isoforms of CD44 (CD44v) rely on the activity of the cystine transporter subunit xCT for control of their redox status. xCT inhibition selectively induces apoptosis in CD44v-expressing tumor cells without affecting CD44v-negative differentiated cells in the same tumor. In contrast to CD44v-expressing undifferentiated cells, CD44v-negative differentiated cells manifest EGF receptor (EGFR) activation and rely on EGFR activity for their survival. Combined treatment with inhibitors of xCT-dependent cystine transport and of EGFR resulted in a synergistic reduction of EGFR-expressing HNSCC tumor growth. Thus, xCT-targeted therapy may deplete CD44v-expressing undifferentiated HNSCC cells and concurrently sensitize the remaining differentiating cells to available treatments including EGFR-targeted therapy.
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Affiliation(s)
- Momoko Yoshikawa
- Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, School of Medicine, Keio University, Shinjuku-ku, Japan
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