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Mitrić A, Castellano I. Targeting gamma-glutamyl transpeptidase: A pleiotropic enzyme involved in glutathione metabolism and in the control of redox homeostasis. Free Radic Biol Med 2023; 208:672-683. [PMID: 37739139 DOI: 10.1016/j.freeradbiomed.2023.09.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Gamma-glutamyl transpeptidase (GGT) is an enzyme located on the outer membrane of the cells where it regulates the metabolism of glutathione (GSH), the most abundant intracellular antioxidant thiol. GGT plays a key role in the control of redox homeostasis, by hydrolyzing extracellular GSH and providing the cell with the recovery of cysteine, which is necessary for de novo intracellular GSH and protein biosynthesis. Therefore, the upregulation of GGT confers to the cell greater resistance to oxidative stress and the advantage of growing fast. Indeed, GGT is upregulated in inflammatory conditions and in the progression of various human tumors and it is involved in many physiological disorders related to oxidative stress, such as cardiovascular disease and diabetes. Currently, increased GGT expression is considered a marker of liver damage, cancer, and low-grade chronic inflammation. This review addresses the current knowledge on the structure-function relationship of GGT, focusing on human GGT, and provides information on the pleiotropic biological role and relevance of the enzyme as a target of drugs aimed at alleviating oxidative stress-related diseases. The development of new GGT inhibitors is critically discussed, as are the advantages and disadvantages of their potential use in clinics. Considering its pleiotropic activities and evolved functions, GGT is a potential "moonlighting protein".
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Affiliation(s)
- Aleksandra Mitrić
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Immacolata Castellano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131, Naples, Italy; Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy.
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Antihelminthic effect of thymoquinone against biliary amphistome, Gigantocotyle explanatum. Exp Parasitol 2022; 243:108421. [DOI: 10.1016/j.exppara.2022.108421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 11/08/2022]
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Grace VMB, Saranya S, Wilson DD. Protective role of All Trans Retinoic Acid on B16F10 melanoma cell line metastasis in C57BL/6 mice by enhancing RAR- β protein and homeostasis maintenance. J Histotechnol 2021; 44:127-138. [PMID: 33947313 DOI: 10.1080/01478885.2021.1896291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lung cancer is the leading cancer according to the World Health Organization (WHO), resulting in highest death rate worldwide due to the high level of metastasis. Hence, the drugs that protect from metastasis either as an adjuvant or a primary therapeutic agent may help to reduce the death rate. In this study, All Trans Retinoic Acid (ATRA) was tested for its action against metastatic lodging of B16F10 melanoma cells in the lung and liver of the C57BL/6 mouse model. Serum, lung and liver were evaluated biochemically for the cancer associated changes. Metastatic cancer development was confirmed by tumor nodule formation and histopathological analysis. RAR-β protein expression was analyzed by immunohistochemistry and histopathology. ATRA treated mice showed a percentage of inhibition on metastatic tumor growth in lung and liver and a corresponding protection against pathological changes in these organs. Cholesterol and γ-Glutamyl Transferase (GGT) levels found in cancer induced mice were reduced in the ATRA treated group. As compared to the normal group, lung tissue from cell line induced cancer control group had less RAR-β protein expression while the ATRA treated group showed enhanced RAR-β protein expression. This indicates that the anti-metastasis effects of ATRA might have shown the induction of RAR-β expression and subsequent molecular signaling pathways to regulate the homeostasis of biochemical changes. This study demonstrated the capability of ATRA to prevent the establishment of metastasis by the melanoma cell line into the lung and liver of experimental mice.
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Affiliation(s)
- V M Berlin Grace
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, India
| | - S Saranya
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, India
| | - D David Wilson
- School of Arts and Sciences, Karunya Institute of Technology and Sciences, Coimbatore, India
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Corti A, Bonetti J, Dominici S, Piaggi S, Fierabracci V, Foddis R, Pompella A. Induction of Gamma-Glutamyltransferase Activity and Consequent Pro-oxidant Reactions in Human Macrophages Exposed to Crocidolite Asbestos. Toxicol Sci 2020; 177:476-482. [PMID: 31388672 DOI: 10.1093/toxsci/kfz175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Asbestos is the main causative agent of malignant pleural mesothelioma. The variety known as crocidolite (blue asbestos) owns the highest pathogenic potential, due to the dimensions of its fibers as well as to its content of iron. The latter can in fact react with macrophage-derived hydrogen peroxide in the so called Fenton reaction, giving rise to highly reactive and mutagenic hydroxyl radical. On the other hand, hydroxyl radical can as well originate after thiol-dependent reduction of iron, a process capable of starting its redox cycling. Previous studies showed that glutathione (GSH) is one such thiol, and that cellular gamma-glutamyltransferase (GGT) can efficiently potentiate GSH-dependent iron redox cycling and consequent oxidative stress. As GGT is expressed in macrophages and is released upon their activation, the present study was aimed at verifying the hypothesis that GSH/GGT-dependent redox reactions may participate in the oxidative stress following the activation of macrophages induced by crocidolite asbestos. Experiments in acellular systems confirmed that GGT-mediated metabolism of GSH can potentiate crocidolite-dependent production of superoxide anion, through the production of highly reactive dipeptide thiol cysteinyl-glycine. Cultured THP-1 macrophagic cells, as well as isolated monocytes obtained from healthy donors and differentiated to macrophages in vitro, were investigated as to their expression of GGT and the effects of exposure to crocidolite. The results show that crocidolite asbestos at subtoxic concentrations (50-250 ng/1000 cells) can upregulate GGT expression, which raises the possibility that macrophage-initiated, GSH/GGT-dependent pro-oxidant reactions may participate in the pathogenesis of tissue damage and inflammation consequent to crocidolite intoxication.
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Affiliation(s)
- Alessandro Corti
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
| | | | - Silvia Dominici
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
| | - Simona Piaggi
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
| | - Vanna Fierabracci
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
| | - Rudy Foddis
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
| | - Alfonso Pompella
- Department of Translational Research NTMS, University of Pisa Medical School, Pisa 56126, Italy
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Bjørklund G, Rajib SA, Saffoon N, Pen JJ, Chirumbolo S. Insights on Melatonin as an Active Pharmacological Molecule in Cancer Prevention: What's New? Curr Med Chem 2019; 26:6304-6320. [PMID: 29714136 DOI: 10.2174/0929867325666180501094850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/10/2018] [Accepted: 04/18/2018] [Indexed: 12/12/2022]
Abstract
Along with playing an important role in circadian rhythm, melatonin is thought to play a significant role in preventing cells from damage, as well as in the inhibition of growth and in triggering apoptosis in malignant cells. Its relationship with circadian rhythms, energetic homeostasis, diet, and metabolism, is fundamental to achieve a better comprehension of how melatonin has been considered a chemopreventive molecule, though very few papers dealing with this issue. In this article, we tried to review the most recent evidence regarding the protective as well as the antitumoral mechanisms of melatonin, as related to diet and metabolic balance. From different studies, it was evident that an intracellular antioxidant defense mechanism is activated by upregulating an antioxidant gene battery in the presence of high-dose melatonin in malignant cells. Like other broad-spectrum antioxidant molecules, melatonin plays a vital role in killing tumor cells, preventing metastasis, and simultaneously keeping normal cells protected from oxidative stress and other types of tissue damage.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | | | - Nadia Saffoon
- Department of Pharmacy and Forensic Science, Faculty of Life Science and Medicine, King's College London, London, United Kingdom
| | - Joeri J Pen
- Diabetes Clinic, Department of Internal Medicine, UZ Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Department of Nutrition, UZ Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Dominici S, Visvikis A, Pieri L, Paolicchi A, Valentini MA, Comporti M, Pompella A. Redox Modulation of NF-κB Nuclear Translocation and DNA Binding in Metastatic Melanoma. The Role of Endogenous and γ-Glutamyl Transferase-Dependent Oxidative Stress. TUMORI JOURNAL 2018; 89:426-33. [PMID: 14606649 DOI: 10.1177/030089160308900416] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aims and background The transcription factor NF-κB is implicated in the expression of genes involved in cell proliferation, apoptosis and metastasis. In melanoma, high constitutive levels of NF-κB activation are usually observed. NF-κB is regulated by oxidation/reduction (redox) processes, and the occurrence of constitutive oxidative stress in melanoma cells has been documented. Recent studies of our laboratories showed that the membrane-bound gamma-glutamyl transferase (GGT) enzyme activity – expressed by a number of malignancies, including melanoma – can act as a basal source of superoxide, hydrogen peroxide and other prooxidants. Methods In the present study we utilized the 2/60 clone of Me665/2 human metastatic melanoma, which displays high levels of GGT activity, in order to verify if the presence of this enzyme - through the promotion of redox processes - may influence the activation status of NF-κB. The latter was evaluated by determining the nuclear translocation of the p65 subunit (by immunoblot), the DNA binding of NF-kB (by elec-trophoretic mobility shift assay) and its transcriptional activity (by gene transactivation studies). Results Me665/2/60 cells displayed a basal production of hydrogen peroxide. Stimulation of GGT activity by its substrates glutathione and glycyl-glycine caused additional production of hydrogen peroxide, up to levels approx. double the basal levels. Nuclear translocation of the NF-κB p65 subunit, DNA-binding and gene transactivation were thus investigated in Me665/2/60 cells whose GGT activity was modulated by means of substrates or inhibitors. Stimulation of GGT activity resulted in increased nuclear translocation of p65, while on the other hand NF-κB DNA binding and gene transactivation were paradoxically decreased. NF-κB DNA binding could be restored by treating cell lysates with the thiol-re-ducing agent dithiothreitol (DTT). Treatment of cells with exogenous hydrogen peroxide did not affect NF-κB activation status. Conclusions Altogether, the data obtained indicate that GGT activity may impair the redox status of thiols that is critical for NF-κB DNA binding and gene transactivation, through the production of prooxidant species allegedly distinct from hydrogen peroxide. GGT activity therefore appears to be an additional factor in modulation of NF-κB transcriptional activity in melanoma, capable of hindering NF-κB DNA binding even in conditions where continuous oxidative stress would favor NF-κB nuclear translocation.
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Affiliation(s)
- Silvia Dominici
- Department of Experimental Pathology, University of Pisa Medical School, Pisa, Italy
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Tiwari AKM, Mahdi AA, Mishra S. Assessment of liver function in pregnant anemic women upon oral iron and folic acid supplementation. J Gynecol Obstet Hum Reprod 2017; 47:45-49. [PMID: 29196155 DOI: 10.1016/j.jogoh.2017.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/11/2017] [Accepted: 11/23/2017] [Indexed: 11/28/2022]
Abstract
Oral iron therapy is the most widely prescribed treatment for iron deficiency anemia. However, oral iron supplementation may also lead to various health problems. The recognition of these physiological variations is essential for the diagnosis of liver diseases during the course of pregnancy. Therefore, the objective of this study was to assess the variations in levels of routine liver function tests (LFTs) in pregnant women before and after iron and folic acid treatment. Iron and folic acid was supplemented to 500 normal pregnant anemic women (mild=200, moderate=200 and severe=100) and 100 age matched normal pregnant non-anemic as controls daily for 100 days. Blood index values and liver function parameters were precisely monitored. Hemoglobin (Hb), total protein (TP), iron (Fe), albumin and alkaline phosphatase (ALP) levels were found increased (P<0.001; P<0.01; P<0.05) after treatment in mild, moderate, severe and control, respectively. Lipid peroxidation (LPx), aspartate transaminase (AST) and alanine transaminase (ALT) were increased in pretreated mild, moderate and severe groups and further increased after all treated subjects. Moreover, gamma-glutamyl transpeptidase (GGT) was found to decrease in pre and posttreated subjects. Treatment with iron and folic acid although has remarkable efficacy for Hb and body iron stores although for the cost of increasing the associated compartment of total bilirubin, AST and ALT concomitant with decreased GGT levels. Data obtained from the present study provide new insights into the mandatory application of liver function tests likely to be monitored at regular and specific intervals during the course of pregnancy.
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Affiliation(s)
- A K M Tiwari
- Department of Biochemistry, King George's Medical University, Shahamina Road, Lucknow 226003, India; Department of Biotechnology, School of Engineering & Technology, IFTM University, Moradabad, India
| | - A A Mahdi
- Department of Biochemistry, King George's Medical University, Shahamina Road, Lucknow 226003, India.
| | - S Mishra
- Department of Biotechnology, School of Engineering & Technology, IFTM University, Moradabad, India
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Wang Q, Shu X, Dong Y, Zhou J, Teng R, Shen J, Chen Y, Dong M, Zhang W, Huang Y, Xie S, Wei Q, Zhao W, Chen W, Yuan X, Qi X, Wang L. Tumor and serum gamma-glutamyl transpeptidase, new prognostic and molecular interpretation of an old biomarker in gastric cancer. Oncotarget 2017; 8:36171-36184. [PMID: 28404903 PMCID: PMC5482647 DOI: 10.18632/oncotarget.15609] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/24/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Gastric Cancer is one of the most lethal malignancies worldwide. Gamma-glutamyl transpeptidase (GGT) is an enzyme mainly involved in cellular glutathione homeostasis. We aim to explore the clinical value of GGT in gastric cancer. RESULTS Among 322 patients enrolled, 65/82 patients were determined as GGT positive in serum/tumor, respectively. High tumor GGT expression is significantly associated with lymph node metastasis, histological subtype, and Her2 expression. Kaplan-Meier curve shows that high tumor GGT patients have shorter overall survival (P log-rank=0.001) and progress-free survival (P log-rank =0.001). Patients with both high tumor and serum GGT have the poorest prognosis. The multivariable Cox analysis shows that the hazard ratio of overall survival for high tumor GGT is 1.69 (95% CI 1.19-2.37). High serum GGT is a poor prognostic factor in adjuvant chemotherapy hazard ratio=2.18, 95%CI (1.15-4.47). These findings were further validated in six online datasets. Gene Sets Enrichment Analysis showed that GGT promotes cancer progression through EMT, KRAS, SRC and PKCA pathways. METHODS Tumor GGT and serum GGT levels were evaluated with immuno-histochemistry staining and enzymatic assay, respectively. Kaplan-Meier curve and Cox regression model were used to test the association between GGT and gastric cancer prognosis. Independent datasets from Gene Expression Omnibus and Gene Sets Enrichment Analysis were applied to validate the findings and explore the potential mechanisms. CONCLUSION Both tumor GGT and serum GGT are poor prognostic factors in gastric cancer. Patients with high tumor and serum GGT levels require more intense treatment and follow-up.
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Affiliation(s)
- Qinchuan Wang
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiang Shu
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Yong Dong
- Department of Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jichun Zhou
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Rongyue Teng
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianguo Shen
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yongxia Chen
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Mingjun Dong
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjun Zhang
- Zhejiang Academy of Medical Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Yasheng Huang
- Department of Unrology, Hangzhou Chinese Medicine Hospital, Hangzhou, China
| | - Shuduo Xie
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qun Wei
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenhe Zhao
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjun Chen
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoming Yuan
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xu Qi
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Linbo Wang
- Department of Surgical Oncology, Affiliated Sir Runrun Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Cappiello M, Spinelli M, Mormino M, Renzone G, Scaloni A, Moschini R, Balestri F, Mura U, Del-Corso A. Purification and characterization of a Cys-Gly hydrolase from the gastropod mollusk, Patella caerulea. J Enzyme Inhib Med Chem 2016; 31:1560-5. [PMID: 27541739 DOI: 10.3109/14756366.2016.1158170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A magnesium-dependent cysteinyl-glycine hydrolyzing enzyme from the gastropod mollusk Patella caerulea was purified to electrophoretic homogeneity through a simple and rapid purification protocol. The molecular masses of the native protein and the subunit suggest that the enzyme has a homohexameric structure. Structural data in combination with kinetic parameters determined with Cys-Gly and compared with Leu-Gly as a substrate, indicate that the purified enzyme is a member of the peptidase family M17. The finding that an enzyme of the peptidase family M17 is responsible also in mollusks for the breakdown of Cys-Gly confirms the important role of this peptidase family in the glutathione metabolism.
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Affiliation(s)
- Mario Cappiello
- a Biology-Biochemistry Unit, University of Pisa , Pisa , Italy and
| | - Matteo Spinelli
- a Biology-Biochemistry Unit, University of Pisa , Pisa , Italy and
| | - Maurizio Mormino
- a Biology-Biochemistry Unit, University of Pisa , Pisa , Italy and
| | - Giovanni Renzone
- b ISPAAM-Proteomics & Mass Spectrometry Laboratory, National Research Council , Naples , Italy
| | - Andrea Scaloni
- b ISPAAM-Proteomics & Mass Spectrometry Laboratory, National Research Council , Naples , Italy
| | - Roberta Moschini
- a Biology-Biochemistry Unit, University of Pisa , Pisa , Italy and
| | | | - Umberto Mura
- a Biology-Biochemistry Unit, University of Pisa , Pisa , Italy and
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Preyer O, Johansen D, Holly J, Stocks T, Pompella A, Nagel G, Concin H, Ulmer H, Concin N. γ-Glutamyltransferase and Breast Cancer Risk Beyond Alcohol Consumption and Other Life Style Factors - A Pooled Cohort Analysis. PLoS One 2016; 11:e0149122. [PMID: 26863311 PMCID: PMC4749274 DOI: 10.1371/journal.pone.0149122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 01/27/2016] [Indexed: 01/05/2023] Open
Abstract
Objective Elevated γ-Glutamyltransferase serum levels are associated with increased risk of overall cancer incidence and several site-specific malignancies. In the present prospective study we report on the associations of serum γ-Glutamyltransferase with the risk of breast cancer in a pooled population-based cohort considering established life style risk factors. Methods Two cohorts were included in the present study, i.e. the Vorarlberg (n = 97,268) and the Malmoe cohort (n = 9,790). Cox proportional hazards regression models were fitted to estimate HRs for risk of breast cancer. Results In multivariate analysis adjusted for age, body mass index and smoking status, women with γ-Glutamyltransferase levels in the top quartile were at significantly higher risk for breast cancer compared to women in the lowest quartile (HR 1.21, 95% CI 1.09 to 1.35; p = 0.005). In the subgroup analysis of the Malmoe cohort, γ-Glutamyltransferase remained an independent risk factor for breast cancer when additionally considering alcohol intake. A statistically significant increase in risk was seen in women with γ-Glutamyltransferase-levels in the top versus lowest quartile in a multivariate model adjusted for age, body mass index, smoking status, physical activity, parity, oral contraceptive-use and alcohol consumption (HR 1.37, 95% CI 1.11–1.69, p = 0.006). Conclusion Our findings identified γ-Glutamyltransferase as an independent risk factor for breast cancer beyond the consumption of alcohol and other life style risk factors.
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Affiliation(s)
- Oliver Preyer
- Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria
| | | | - Jessica Holly
- Department of Obstetrics and Gynaecology, Innsbruck Medical University, Innsbruck, Austria
| | - Tanja Stocks
- Lund University Diabetes Centre, Diabetes and Cardiovascular Disease—Genetic Epidemiology Department of Clinical Sciences Malmö, CRC, Malmoe, Sweden
| | - Alfonso Pompella
- Department of Experimental Pathology, University of Pisa, Medical School, Pisa, Italy
| | - Gabriele Nagel
- Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Hans Concin
- Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria
| | - Hanno Ulmer
- Department of Medical Statistics, Informatics and Health Economics, Innsbruck Medical University, Innsbruck, Austria
| | - Nicole Concin
- Department of Obstetrics and Gynaecology, Innsbruck Medical University, Innsbruck, Austria
- * E-mail:
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11
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Ramsay EE, Dilda PJ. Glutathione S-conjugates as prodrugs to target drug-resistant tumors. Front Pharmacol 2014; 5:181. [PMID: 25157234 PMCID: PMC4127970 DOI: 10.3389/fphar.2014.00181] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/16/2014] [Indexed: 01/08/2023] Open
Abstract
Living organisms are continuously exposed to xenobiotics. The major phase of enzymatic detoxification in many species is the conjugation of activated xenobiotics to reduced glutathione (GSH) catalyzed by the glutathione-S-transferase (GST). It has been reported that some compounds, once transformed into glutathione S-conjugates, enter the mercapturic acid pathway whose end products are highly reactive and toxic for the cell responsible for their production. The cytotoxicity of these GSH conjugates depends essentially on GST and gamma-glutamyl transferases (γGT), the enzymes which initiate the mercapturic acid synthesis pathway. Numerous studies support the view that the expression of GST and γGT in cancer cells represents an important factor in the appearance of a more aggressive and resistant phenotype. High levels of tumor GST and γGT expression were employed to selectively target tumor with GST- or γGT-activated drugs. This strategy, explored over the last two decades, has recently been successful using GST-activated nitrogen mustard (TLK286) and γGT-activated arsenic-based (GSAO and Darinaparsin) prodrugs confirming the potential of GSH-conjugates as anticancer drugs.
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Affiliation(s)
- Emma E Ramsay
- Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Pierre J Dilda
- Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
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Kim SJ, Han SW, Lee DJ, Kim KM, Joo NS. Higher Serum Heavy Metal May Be Related with Higher Serum gamma-Glutamyltransferase Concentration in Koreans: Analysis of the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1, 2, 2010, 2011). Korean J Fam Med 2014; 35:74-80. [PMID: 24724002 PMCID: PMC3978188 DOI: 10.4082/kjfm.2014.35.2.74] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 02/21/2014] [Indexed: 11/16/2022] Open
Abstract
Background Abnormal serum gamma-glutamyltransferase (γ-GT) may be an early and sensitive marker for oxidative stress. This study was performed to evaluate the association between serum heavy metals and γ-GT concentration. Methods This study is a cross-sectional analysis based on data from Korean National Health and Nutrition Examination Survey (V-1, 2, 2010, 2011) regarding serum heavy metal concentrations (lead, mercury, and cadmium) as well as serum γ-GT. Serum heavy metals were categorized into tertiles, and serum γ-GT concentration was compared using an analysis of covariance test after relevant variable adjustments. In addition, we evaluated the odds ratio (OR) of having the highest tertile of serum γ-GT in each heavy metal tertile using logistic regression. Results The mean serum lead, mercury, and cadmium concentrations were 2.67, 5.08, and 1.02 µg/dL in men and 1.95, 3.60, and 1.21 µg/dL in women, respectively. Partial correlation showed a significant positive relation between each heavy metal and serum γ-GT concentration. Comparing serum γ-GT concentration by the tertile of each heavy metal, serum γ-GT concentration showed a significant increase as the tertiles of serum mercury and cadmium in men and that of serum mercury in women increased, but not with lead. The OR of having the highest tertile of serum γ-GT was significant for cadmium in men (OR, 4.02; 95% confidence interval [CI], 2.54 to 6.35) and mercury in women (OR, 2.00; 95% CI, 1.29 to 3.10) in the top tertile of each heavy metal. Conclusion Higher serum heavy metal concentration may be related with higher serum γ-GT concentration. In particular, serum cadmium in men and mercury in women showed significant correlation with serum γ-GT concentration.
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Affiliation(s)
- Sung-Jin Kim
- Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon, Korea
| | - Sung-Woo Han
- Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon, Korea
| | - Duck-Joo Lee
- Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon, Korea
| | - Kwang-Min Kim
- Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon, Korea
| | - Nam-Seok Joo
- Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon, Korea
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Torres Mena JE, Sánchez Rodríguez R, Quintanar Jurado V, Mojica Espinosa R, Del Pozo Yauner L, Meléndez Zajgla J, Villa Treviño S, Pérez Carreón JI. Laser capture microdissection after γ-glutamyl transferase histochemistry: An optimization for gene expression analysis. Anal Biochem 2014; 447:126-32. [DOI: 10.1016/j.ab.2013.11.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 11/16/2022]
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14
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Zhang G, Ducatelle R, Pasmans F, D’Herde K, Huang L, Smet A, Haesebrouck F, Flahou B. Effects of Helicobacter suis γ-glutamyl transpeptidase on lymphocytes: modulation by glutamine and glutathione supplementation and outer membrane vesicles as a putative delivery route of the enzyme. PLoS One 2013; 8:e77966. [PMID: 24147103 PMCID: PMC3797756 DOI: 10.1371/journal.pone.0077966] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 09/08/2013] [Indexed: 12/11/2022] Open
Abstract
Helicobacter (H.) suis colonizes the stomach of the majority of pigs as well as a minority of humans worldwide. Infection causes chronic inflammation in the stomach of the host, however without an effective clearance of the bacteria. Currently, no information is available about possible mechanisms H. suis utilizes to interfere with the host immune response. This study describes the effect on various lymphocytes of the γ-glutamyl transpeptidase (GGT) from H. suis. Compared to whole cell lysate from wild-type H. suis, lysate from a H. suis ggt mutant strain showed a decrease of the capacity to inhibit Jurkat T cell proliferation. Incubation of Jurkat T cells with recombinantly expressed H. suis GGT resulted in an impaired proliferation, and cell death was shown to be involved. A similar but more pronounced inhibitory effect was also seen on primary murine CD4(+) T cells, CD8(+) T cells, and CD19(+) B cells. Supplementation with known GGT substrates was able to modulate the observed effects. Glutamine restored normal proliferation of the cells, whereas supplementation with reduced glutathione strengthened the H. suis GGT-mediated inhibition of proliferation. H. suis GGT treatment abolished secretion of IL-4 and IL-17 by CD4(+) T cells, without affecting secretion of IFN-γ. Finally, H. suis outer membrane vesicles (OMV) were identified as a possible delivery route of H. suis GGT to lymphocytes residing in the deeper mucosal layers. Thus far, this study is the first to report that the effects on lymphocytes of this enzyme, not only important for H. suis metabolism but also for that of other Helicobacter species, depend on the degradation of two specific substrates: glutamine and reduced glutatione. This will provide new insights into the pathogenic mechanisms of H. suis infection in particular and infection with gastric helicobacters in general.
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Affiliation(s)
- Guangzhi Zhang
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- * E-mail:
| | - Richard Ducatelle
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katharina D’Herde
- Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Liping Huang
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Annemieke Smet
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Bram Flahou
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Ruzza P, Calderan A. Glutathione Transferase (GST)-Activated Prodrugs. Pharmaceutics 2013; 5:220-31. [PMID: 24300447 PMCID: PMC3834953 DOI: 10.3390/pharmaceutics5020220] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 12/19/2022] Open
Abstract
Glutathione transferase (formerly GST) catalyzes the inactivation of various electrophile-producing anticancer agents via conjugation to the tripeptide glutathione. Moreover, several data link the overexpression of some GSTs, in particular GSTP1-1, to both natural and acquired resistance to various structurally unrelated anticancer drugs. Tumor overexpression of these proteins has provided a rationale for the search of GST inhibitors and GST activated cytotoxic prodrugs. In the present review we discuss the current structural and pharmacological knowledge of GST-activated cytotoxic compounds.
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Affiliation(s)
- Paolo Ruzza
- Institute of Biomolecular Chemistry of CNR, Padova Unit, Via Marzolo 1, Padova 35131, Italy.
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16
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Van Phan T, Sul OJ, Ke K, Lee MH, Kim WK, Cho YS, Kim HJ, Kim SY, Chung HT, Choi HS. Carbon monoxide protects against ovariectomy-induced bone loss by inhibiting osteoclastogenesis. Biochem Pharmacol 2013; 85:1145-52. [DOI: 10.1016/j.bcp.2013.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 12/15/2022]
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17
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Castellano I, Merlino A. Gamma-Glutamyl Transpeptidases: Structure and Function. GAMMA-GLUTAMYL TRANSPEPTIDASES 2013. [DOI: 10.1007/978-3-0348-0682-4_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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18
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Expression profiling of attenuated mitochondrial function identifies retrograde signals in Drosophila. G3-GENES GENOMES GENETICS 2012; 2:843-51. [PMID: 22908033 PMCID: PMC3411240 DOI: 10.1534/g3.112.002584] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/18/2012] [Indexed: 01/12/2023]
Abstract
Mitochondria are able to modulate cell state and fate during normal and pathophysiologic conditions through a nuclear-mediated mechanism collectively termed as a retrograde response. Our previous studies in Drosophila melanogaster have clearly established that progress through the cell cycle is precisely regulated by the intrinsic activity of the mitochondrion by specific signaling cascades mounted by the cell. As a means to further our understanding of how mitochondrial energy status affects nuclear control of basic cell decisions, we have employed Affymetrix microarray-based transcriptional profiling of Drosophila S2 cells knocked down for the gene encoding subunit Va of the complex IV of the mitochondrial electron transport chain. The profiling data identify transcriptional upregulation of glycolytic genes, and metabolic studies confirm this increase in glycolysis. The data provide a model of the shift of metabolism from a predominately oxidative state toward a predominately aerobic glycolytic state mediated through transcriptional control. The transcriptional changes alter many signaling systems, including p53, insulin, hypoxia-induced factor α, and conserved mitochondrial retrograde responses. This rich dataset provides many novel targets for further understanding the mechanism whereby the mitochondrion manages energy substrate disposition and directs cellular fate decisions.
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Flahou B, Haesebrouck F, Chiers K, Van Deun K, De Smet L, Devreese B, Vandenberghe I, Favoreel H, Smet A, Pasmans F, D'Herde K, Ducatelle R. Gastric epithelial cell death caused by Helicobacter suis and Helicobacter pylori γ-glutamyl transpeptidase is mainly glutathione degradation-dependent. Cell Microbiol 2011; 13:1933-55. [DOI: 10.1111/j.1462-5822.2011.01682.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Jung CH, Yu JH, Bae SJ, Koh EH, Kim MS, Park JY, Kim HK, Lee WJ. Serum gamma-glutamyltransferase is associated with arterial stiffness in healthy individuals. Clin Endocrinol (Oxf) 2011; 75:328-34. [PMID: 21521327 DOI: 10.1111/j.1365-2265.2011.04060.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference. DESIGN This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea. SUBJECTS AND MEASUREMENTS Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening examination. RESULTS In both men and women, we observed positive linearity between GGT quartiles and body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, uric acid, high-sensitive C-reactive protein (hsCRP) and homeostatic model assessment of insulin resistance (HOMA-IR) score (P for trends < 0·001). The proportion of individuals with diabetes, hypertension increased as the GGT quartile increased (P for trends < 0·001). Age-adjusted mean baPWV increased gradually in both males and females according to GGT quartiles (P for trends < 0·001 in both genders). The odds for higher baPWV (i.e. >75th percentile in each sex) were significantly higher in the highest compared with the lowest GGT quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 1·63, 95% CI = 1·21-2·20] and women (OR = 1·56, 95% CI = 1·08-2·27). CONCLUSIONS These results suggest that GGT is independently associated with the increased level of arterial stiffness both in men and in women and the association between them appears to be stronger in men compared to women.
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Affiliation(s)
- Chang Hee Jung
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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21
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Dreifuss AA, Bastos-Pereira AL, Avila TV, Soley BDS, Rivero AJ, Aguilar JL, Acco A. Antitumoral and antioxidant effects of a hydroalcoholic extract of cat's claw (Uncaria tomentosa) (Willd. Ex Roem. & Schult) in an in vivo carcinosarcoma model. JOURNAL OF ETHNOPHARMACOLOGY 2010; 130:127-133. [PMID: 20435132 DOI: 10.1016/j.jep.2010.04.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 04/05/2010] [Accepted: 04/20/2010] [Indexed: 05/29/2023]
Abstract
AIM OF THE STUDY The present work intended to study the antitumoral and antioxidant effects of Uncaria tomentosa (UT) hydroalcoholic extract in the Walker-256 cancer model. METHODS AND MATERIALS Walker-256 cells were subcutaneously inoculated in the pelvic limb of male Wistar rats. Daily gavage with UT extract (10, 50 or 100 mg kg(-1), Groups UT) or saline solution (Control, Group C) was subsequently initiated, until 14 days afterwards. For some parameters, a group of healthy rats (Baseline, Group B) was added. At the end of treatment the following parameters were evaluated: (a) tumor volume and mass; (b) plasmatic concentration of urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and lactate dehydrogenase (LDH); (c) hepatic and tumoral activity of catalase (CAT) and superoxide dismutase (SOD), as well as the rate of lipid peroxidation (LPO) and gluthatione (GSH); and (d) hepatic glutathione-S-transferase (GST) activity. The reactivity of UT extract with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was assessed in parallel. RESULTS UT hydroalcoholic extract successfully reduced the tumor growth. In addition, treatment with UT reduced the activity of AST, which had been increased as a result of tumor inoculation, thus attempting to return it to normal levels. UT did not reverse the increase of LDH and GGT plasma levels, although all doses were remarkably effective in reducing urea plasma levels. An important in vitro free radical-scavenging activity was detected at various concentrations of UT extract (1-300 microg mL(-1)). Treatment also resulted in increased CAT activity in liver, while decreasing it in tumor tissue. SOD activity was reduced in liver as well as in tumor, compared to Group C. No statistical significance concerning ALT, GST, LPO or GSH were observed. CONCLUSIONS This data represent an in vivo demonstration of both antitumoral and antioxidant effects of UT hydroalcoholic extract. The antineoplastic activity may result, partially at least, from the ability of UT to regulate redox and metabolism homeostasis.
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22
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Corti A, Duarte TL, Giommarelli C, De Tata V, Paolicchi A, Jones GDD, Pompella A. Membrane gamma-glutamyl transferase activity promotes iron-dependent oxidative DNA damage in melanoma cells. Mutat Res 2009; 669:112-21. [PMID: 19505483 DOI: 10.1016/j.mrfmmm.2009.05.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/09/2009] [Accepted: 05/27/2009] [Indexed: 11/28/2022]
Abstract
A number of recent observations have suggested a potential role for membrane-bound gamma-glutamyltransferase (GGT) in tumor progression and appearance of more aggressive and resistant phenotypes, through redox interactions leading to production of reactive oxygen species. The present study was aimed to evaluate whether such pro-oxidant activity of GGT can promote oxidative DNA damage, thus contributing to cancer genomic instability. Human GGT-transfected melanoma cells were studied, and DNA damage was measured by using the alkaline comet assay. Our results indicate that higher levels of GGT activity are associated with higher levels of background DNA damage and oxidized bases. This association cannot be explained by differences in cell cycle distribution or apoptotic rates. GGT-over-expressing cells also presented with a markedly higher glucose uptake, a phenomenon potentially leading to higher metabolic rate and oxidative DNA damage. Anyway, when GGT-over-expressing cells were incubated in the presence of GGT substrates and a source of catalytic iron, increased levels of DNA damage and oxidized bases were observed, an effect completely prevented in the presence of GGT inhibitors or various antioxidants.The findings reported indicate that GGT activity is able to promote iron-dependent DNA oxidative damage, thus potentially representing an important mechanism in initiation/progression of neoplastic transformation.
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Affiliation(s)
- Alessandro Corti
- Dipartimento di Patologia Sperimentale, Biotecnologie Mediche, Infettivologia ed Epidemiologia, University of Pisa, Pisa, Italy.
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23
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Ferretti M, Destro T, Tosatto SCE, La Rocca N, Rascio N, Masi A. Gamma-glutamyl transferase in the cell wall participates in extracellular glutathione salvage from the root apoplast. THE NEW PHYTOLOGIST 2009; 181:115-126. [PMID: 19076720 DOI: 10.1111/j.1469-8137.2008.02653.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The molecular properties and subcellular location of bound gamma-glutamyl transferase (GGT) were studied, and an experimental setup devised to assess its functions in barley roots. Enzyme histochemistry was used to detect GGT activity at tissue level; immunocytochemistry to localize the protein at subcellular level; and modelling studies to investigate its surface charge properties. GGT activity in vivo was measured for the first time. Functions were explored by applying chemical treatments with inhibitors and the thiol-oxidizing drug diamide, performing time-course chromatographic and spectrophotometric analyses on low-molecular-weight thiols. Gamma-glutamyl transferase activity was found to be high in the root apical region and the protein was anchored to root cell wall components, probably by basic amino acid residues. The results show that GGT is essential to the recovery of apoplastic glutathione provided exogenously or extruded by oxidative treatment. It is demonstrated that GGT activity helps to salvage extracellular glutathione and may contribute to redox control of the extracellular environment, thus providing evidence of a functional role for gamma-glutamyl cycle in roots.
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Affiliation(s)
- M Ferretti
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
| | - T Destro
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
| | - S C E Tosatto
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
| | - N La Rocca
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
| | - N Rascio
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
| | - A Masi
- Department of Agricultural Biotechnology, University of Padova, Viale dell'Universita' 16, I-35020 Legnaro (PD), Italy;Department of Biology, University of Padova, Via Trieste 75, I-35100 Padova, Italy;CRIBI Biotech Centre, University of Padova, Via Trieste 75, I-35100 Padova, Italy
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Kaufmann Y, Todorova VK, Luo S, Klimberg VS. Glutamine Affects Glutathione Recycling Enzymes in a DMBA-Induced Breast Cancer Model. Nutr Cancer 2008; 60:518-25. [DOI: 10.1080/01635580801956501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ozsoy HZ, Sivasubramanian N, Wieder ED, Pedersen S, Mann DL. Oxidative stress promotes ligand-independent and enhanced ligand-dependent tumor necrosis factor receptor signaling. J Biol Chem 2008; 283:23419-28. [PMID: 18544535 DOI: 10.1074/jbc.m802967200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Tumor necrosis factor (TNF) receptor 1 (TNFR1, p55) and 2 (TNFR2, p75) are characterized by several cysteine-rich modules in the extracellular domain, raising the possibility that redox-induced modifications of these cysteine residues might alter TNFR function. To test this possibility, we examined fluorescence resonance energy transfer (FRET) in 293T cells transfected with CFP- and YFP-tagged TNFRs exposed to the thiol oxidant diamide. Treatment with high concentrations of diamide (1 mm) resulted in an increase in the FRET signal that was sensitive to inhibition with the reducing agent dithiothreitol, suggesting that oxidative stress resulted in TNFR self-association. Treatment of cells with low concentrations of diamide (1 mum) that was not sufficient to provoke TNFR self-association resulted in increased TNF-induced FRET signals relative to the untreated cells, suggesting that oxidative stress enhanced ligand-dependent TNFR signaling. Similar findings were obtained when the TNFR1- and TNFR2-transfected cells were pretreated with a cell-impermeable oxidase, DsbA, that catalyzes disulfide bond formation between thiol groups on cysteine residues. The changes in TNFR self-association were functionally significant, because pretreating the HeLa cells and 293T cells resulted in increased TNF-induced NF-kappaB activation and TNF-induced expression of IkappaB and syndecan-4 mRNA levels. Although pretreatment with DsbA did not result in an increase in TNF binding to TNFRs, it resulted in increased TNF-induced activation of NF-kappaB, consistent with an allosteric modification of the TNFRs. Taken together, these results suggest that oxidative stress promotes TNFR receptor self-interaction and ligand-independent and enhanced ligand-dependent TNF signaling.
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Affiliation(s)
- Hatice Z Ozsoy
- Department of Medicine and Molecular Physiology and Biophysics, Winters Center for Heart Failure Research, Baylor College of Medicine, Houston, Texas 77030, USA
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26
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Saijo Y, Utsugi M, Yoshioka E, Horikawa N, Sato T, Gong Y, Kishi R. The relationship of gamma-glutamyltransferase to C-reactive protein and arterial stiffness. Nutr Metab Cardiovasc Dis 2008; 18:211-219. [PMID: 17412574 DOI: 10.1016/j.numecd.2006.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 09/06/2006] [Accepted: 10/05/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND AIMS The relationships between gamma-glutamyltransferase (GGT), C-reactive protein (CRP), and arterial stiffness have not been fully investigated. The aim of this study was to clarify whether serum GGT is related to CRP and arterial stiffness estimated using brachial-ankle pulse wave velocity (baPWV). METHODS AND RESULTS The subjects were 3412 males and 854 females. GGT, CRP, baPWV, and conventional risk factors were evaluated. On multiple regression analysis, after adjustment for the conventional risk factors, log GGT was significantly associated with log CRP in male and female subjects (male subjects: beta=0.168, p<0.0001; female subjects: beta=0.098, p<0.05). After adjustment for the conventional risk factors, log GGT was significantly associated with PWV in male subjects (beta=0.060, p<0.0001), but in female subjects, no significant relationships were found after adjustment (beta=0.007, p=0.82). CONCLUSION These results suggest that GGT is independently associated with an increased level of CRP in both males and females. In addition, in males, GGT is related to an increased level of arterial stiffness.
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Affiliation(s)
- Yasuaki Saijo
- Department of Health Science, Asahikwa Medical College, Midorigaoka, E2-1-1-1, Asahikawa, Hokkaido 078-8510, Japan.
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27
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Pompella A, Corti A, Paolicchi A, Giommarelli C, Zunino F. Gamma-glutamyltransferase, redox regulation and cancer drug resistance. Curr Opin Pharmacol 2007; 7:360-6. [PMID: 17613273 DOI: 10.1016/j.coph.2007.04.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 04/16/2007] [Accepted: 04/26/2007] [Indexed: 01/09/2023]
Abstract
Gamma-glutamyltransferase, a key enzyme of GSH metabolism, can modulate crucial redox-sensitive functions, such as antioxidant/antitoxic defences and cellular proliferative/apoptotic balance, with potential implications in tumour progression and drug resistance. Recent studies have elucidated the mechanisms of GGT involvement in various pathological processes suggesting its potential role as therapeutic target and diagnostic/prognostic marker.
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Affiliation(s)
- Alfonso Pompella
- Dipartimento di Patologia Sperimentale, Università di Pisa, Scuola MedicaVia Roma 55, 56126 Pisa, Italy
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28
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Kwiecień I, Rokita H, Lorenc-Koci E, Sokolowska M, Włodek L. The effect of modulation of gamma-glutamyl transpeptidase and nitric oxide synthase activity on GSH homeostasis in HepG2 cells. Fundam Clin Pharmacol 2007; 21:95-103. [PMID: 17227450 DOI: 10.1111/j.1472-8206.2006.00458.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
High glutathione (GSH) level and elevated gamma-glutamyl transpeptidase (gammaGT) activity are hallmarks of tumor cells. Toxicity of drugs and radiation to the cells is largely dependent on the level of thiols. In the present studies, we attempted to inhibit gammaGT activity in human hepatoblastoma (HepG2) cells to examine whether the administration of gammaGT inhibitors, acivicin (AC) and 1,2,3,4-tetrahydroisoquinoline (TIQ) influences cell proliferation and enhances cytostatic action of doxorubicin (DOX) and cisplatin (CP) on HepG2 cells. The effects of these inhibitors were determined by 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT), BrdU and lactate dehydrogenase (LDH) tests and by estimation of GSH level. Additionally, we investigated the changes in caspase-3 activity, which is a marker of apoptosis. The obtained results showed that the gammaGT inhibitors introduced to the medium alone elicited cytotoxic effect, which was accompanied by an increase in GSH level in the cells. TIQ concomitantly increased caspase-3 activity. Doxorubicin and CP proved to be cytotoxic, and both inhibitors augmented this effect. As well DOX as CP radically decreased GSH levels, whereas gammaGT inhibitors had diverse effects. Therefore, the obtained results confirm that gammaGT inhibitors can enhance pharmacological action of DOX and CP, which may permit clinicians to decrease their doses thereby alleviating side effects. Aminoguanidine (nitric oxide synthase inhibitor) given alone was little cytotoxic to HepG2 cells, while its introduction to the medium together with DOX and CP significantly increased their cytotoxicity. Aminoguanidine on its own did not show any effect on GSH level in HepG2 cells, but markedly and significantly elevated its concentration when added in combination with CP but not with DOX. This indicates that when CP was used as a cytostatic, GSH level rose after treatment with its combination with both AC and aminoguanidine.
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Affiliation(s)
- Inga Kwiecień
- Medical Biochemistry Department, Collegium Medium, Jagiellonian University, Krakow, Poland
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29
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Giustarini D, Dalle-Donne I, Lorenzini S, Milzani A, Rossi R. Age-related influence on thiol, disulfide, and protein-mixed disulfide levels in human plasma. J Gerontol A Biol Sci Med Sci 2006; 61:1030-8. [PMID: 17077195 DOI: 10.1093/gerona/61.10.1030] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, plasma levels of both low-molecular-mass sulfhydryls/disulfides and mixed disulfides with proteins in 41 healthy humans aged 21-92 years were measured, with the aim of assessing whether there is a shift of the thiol/disulfide balance during aging and verifying some of the possible effects of the thiol imbalance. Our data suggest that aging is strictly correlated to a decrease in plasma glutathione and cysteinylglycine with the concomitant increase of most oxidized forms of thiols and a parallel increase in total cysteine and total homocysteine, probably due to an augmented efflux of these amino acids from various organs. The occurrence of two distinct regulatory systems for plasmatic pools of glutathione/cysteinylglycine on the one hand and cysteine/homocysteine on the other hand is hypothesized.
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Affiliation(s)
- Daniela Giustarini
- Department of Neuroscience, Pharmacology Unit, University of Siena, via A. Moro 4, I-53100, Siena, Italy.
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30
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Del Bello B, Moretti D, Gamberucci A, Maellaro E. Cross-talk between calpain and caspase-3/-7 in cisplatin-induced apoptosis of melanoma cells: a major role of calpain inhibition in cell death protection and p53 status. Oncogene 2006; 26:2717-26. [PMID: 17130844 DOI: 10.1038/sj.onc.1210079] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The contribution of different proteolytic systems, in particular calpains and effector caspases, in apoptotic cell death is still controversial. In this paper, we show that during cisplatin-induced apoptosis of human metastatic melanoma cells, calpain activation, as measured in intact cells by two different fluorescent substrates, is an early event, taking place well before caspase-3/-7 activation, and progressively increasing during 48 h of treatment. Such activation appears to be independent from any intracellular calcium imbalance; in fact, an increase of cytosolic calcium along with emptying of the reticular stores occur only at very late stages, uniquely in frankly apoptotic, detached cells. Calpain activation proves to be an early and crucial event in the apoptotic machinery, as demonstrated by the significant protection of cell death in samples co-treated with the calpain inhibitors, MDL 28170, calpeptin and PD 150606, where a variable but significant reduction of both caspase-3/-7 activity and cell detachment is observed. Consistently, such a protective effect can be at least partially due to the impairment of cisplatin-induced p53 activation, occurring early in committed, preapoptotic cells. Furthermore, in late apoptotic cells, calpain activity is also responsible for the formation of a novel p53 proteolytic fragment (approximately 26 kDa), whose function is so far to be elucidated.
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Affiliation(s)
- B Del Bello
- Department of Physiopathology and Experimental Medicine, University of Siena, Siena, Italy
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31
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Palomares T, Castro B, del Olmo M, Iglesias A, Bilbao P, Alonso-Varona A. Influence of the level of γ-glutamyltranspeptidase activity on the response of poorly and moderately differentiated rhabdomyosarcoma cell lines to all-trans-retinoic acid. Anticancer Drugs 2006; 17:1127-39. [PMID: 17075312 DOI: 10.1097/01.cad.0000236308.27962.65] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Differentiation therapy with retinoic acid has been considered a potential approach for treating rhabdomyosarcoma. Analysis of retinoids as differentiating agents for rhabdomyosarcoma is, however, rendered incomplete by the fact that some rhabdomyosarcoma cell lines are retinoic acid resistant. Therefore, the aim of the present work was to study the effect of all-trans-retinoic acid on two rat tumour cell lines, derived from the same rhabdomyosarcoma tumour model (i.e. the moderately differentiated low metastatic F21 cell line and the poorly differentiated high metastatic S4MH cell line), to discover how degree of differentiation and glutathione metabolism influence response to this retinoic acid derivative. We observed that whereas in the S4MH cell line all-trans-retinoic acid induced a significant inhibition of tumorigenic potential, in F21 cells all-trans-retinoic acid enhanced tumour growth and only at a higher dose was there a slight antiproliferative effect. These effects were in consonance with the activity level of gamma-glutamyltranspeptidase, which was significantly increased in F21 cells, but not in S4MH cells, in response to the all-trans-retinoic acid-induced increase in reactive oxygen species. The pro-tumour effect observed in F21 cells was reversed by adding buthionine sulphoximide, a specific cellular glutathione-depleting agent, to the all-trans-retinoic acid treatment. This combination produced a decrease in gamma-glutamyltranspeptidase activity, and an increase in oxidative stress and apoptosis. Our findings suggest that the response to all-trans-retinoic-acid of the tumour cell lines studied is influenced by the strong relationship between intracellular glutathione content, gamma-glutamyltranspeptidase activity and degree of differentiation of the rhabdomyosarcoma cell line, and that this relationship should be taken into account when identifying 'retinoid-sensitive' tumours.
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Affiliation(s)
- Teodoro Palomares
- Department of Surgery, Radiology and Physical Medicine, University of the Basque Country, Leioa, Vizcaya, Spain.
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Franzini M, Corti A, Lorenzini E, Paolicchi A, Pompella A, De Cesare M, Perego P, Gatti L, Leone R, Apostoli P, Zunino F. Modulation of cell growth and cisplatin sensitivity by membrane γ-glutamyltransferase in melanoma cells. Eur J Cancer 2006; 42:2623-30. [PMID: 16928443 DOI: 10.1016/j.ejca.2006.04.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 03/31/2006] [Accepted: 04/07/2006] [Indexed: 12/22/2022]
Abstract
The plasma membrane enzyme gamma-glutamyltransferase (GGT) is regarded as critical for the maintenance of intracellular levels of glutathione (GSH). GGT expression has been implicated in drug resistance through elevation of intracellular GSH. The dependence of intracellular GSH on GGT expression was not conclusively ascertained. The present study was designed to investigate the role of GGT and of intracellular GSH levels in modulating proliferation and sensitivity to cisplatin of melanoma cells. GGT transfection resulted in increased growth, both in vitro and in tumour xenografts. In addition, GGT-transfected cells exhibited reduced sensitivity to cisplatin associated with lower DNA platination. A decrease in intracellular GSH levels, rather than an increase, was observed in GGT-transfected cells; moreover, in cysteine-deficient conditions, the expression of GGT did not provide transfected cells with the ability of utilising extracellular GSH. In conclusion, these results indicate that GGT activity confers a growth advantage unrelated with intracellular glutathione supply, and are consistent with the interpretation that cisplatin resistance is the consequence of modifications of cellular pharmacokinetics as a result of extracellular drug inactivation by thiol metabolites originated by GGT-mediated GSH cleavage.
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Affiliation(s)
- Maria Franzini
- Dipartimento di Patologia Sperimentale BMIE, University of Pisa Medical School, Italy
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Petti C, Molla A, Vegetti C, Ferrone S, Anichini A, Sensi M. Coexpression of NRASQ61Rand BRAFV600Ein Human Melanoma Cells Activates Senescence and Increases Susceptibility to Cell-Mediated Cytotoxicity. Cancer Res 2006; 66:6503-11. [PMID: 16818621 DOI: 10.1158/0008-5472.can-05-4671] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Activating mutations in BRAF and NRAS oncogenes in human melanomas are mutually exclusive. This finding has suggested an epistatic relationship but is consistent even with synthetic lethality. To evaluate the latter possibility, a mutated NRAS(Q61R) oncogene was expressed, under a constitutive or a doxycycline-regulated promoter, in a metastatic melanoma clone (clone 21) harboring an activated BRAF(V600E) oncogene. After the first 10 to 12 in vitro passages, the constitutive NRAS(Q61R) transfectant displayed progressive accumulation in G(0)-G(1) phase of the cell cycle and stained for the senescence-associated beta-galactosidase activity (SA-beta-Gal). Inducible expression of NRAS(Q61R), by the Tet-Off system, in clone 21 cells (21NRAS(61ON)) led to overactivation of the RAS/RAF/mitogen-activated protein kinase signaling pathway and, after the 10th in vitro passage, led to promotion of senescence. This was documented by reduced proliferation, flattened cell morphology, reduced growth in Matrigel, positive staining for SA-beta-Gal, and expression of AMP-activated protein kinase and of the cell cycle inhibitor p21(waf1/Cip1). These effects were detected neither in 21 cells with silenced NRAS(Q61R) (21NRAS(61OFF)) nor in cells transfected with an inducible wild-type NRAS gene (21NRAS(WTON)). In addition, when compared with parental 21 cells, or with 21NRAS(61OFF), 21NRAS(61ON) and constitutive NRAS(Q61R) transfectants cells showed increased susceptibility to cytotoxicity by both HLA class I antigen-restricted and nonspecific T cells and up-regulation of several MHC class I antigen processing machinery components. These results suggest a relationship of synthetic lethality between NRAS and BRAF oncogenes, leading to selection against "double-mutant" cells.
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Affiliation(s)
- Carlotta Petti
- Unit of Immunobiology of Human Tumors, Department of Experimental Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1, 20133 Milan, Italy
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Dominici S, Paolicchi A, Corti A, Maellaro E, Pompella A. Prooxidant reactions promoted by soluble and cell-bound gamma-glutamyltransferase activity. Methods Enzymol 2006; 401:484-501. [PMID: 16399404 DOI: 10.1016/s0076-6879(05)01029-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent studies have provided evidence for the prooxidant roles played by molecular species originating during the catabolism of glutathione (GSH) effected by gamma-glutamyltransferase (GGT), an enzyme normally present in serum and on the outer surface of numerous cell types. The reduction of metal ions by GSH catabolites is capable of inducing the redox cycling processes, leading to the production of reactive oxygen species and other free radicals. Through the action of these reactive compounds, cell membrane GGT activity can ultimately produce oxidative modifications on a variety of molecular targets, involving oxidation and/or S-thiolation of protein thiol groups in the first place. This chapter is a survey of the procedures most suitable to reveal GGT-dependent prooxidant reactions and their effects at the cellular and extracellular level, including methods in histochemistry, cytochemistry, and biochemistry, with special reference to methods for the evaluation of protein thiol redox status.
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Affiliation(s)
- Silvia Dominici
- Department of experimental Pathology, University of Pisa Medical School, Pisa, Italy
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Ruttmann E, Brant LJ, Concin H, Diem G, Rapp K, Ulmer H. Gamma-glutamyltransferase as a risk factor for cardiovascular disease mortality: an epidemiological investigation in a cohort of 163,944 Austrian adults. Circulation 2005; 112:2130-7. [PMID: 16186419 DOI: 10.1161/circulationaha.105.552547] [Citation(s) in RCA: 412] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND There is evidence from recent studies that gamma-glutamyltransferase (GGT) is likely to be associated with cardiovascular disease (CVD). However, few studies to date with sufficient sample size and follow-up investigated the association of GGT with CVD mortality. METHODS AND RESULTS The relation of GGT to the risk of death from CVD was examined in a cohort of 163,944 Austrian adults that was monitored for up to 17 years. To evaluate GGT as an independent predictor, Cox proportional hazards models were calculated, which adjusted for established risk factors. In both men and women, high GGT was significantly (P<0.001) associated with total mortality from CVD, showing a clear dose-response relationship. Adjusted hazard ratios (95% CI) per log GGT increase were 1.66 (1.40 to 1.98) in men and 1.64 (1.36 to 1.97) in women. In men, subgroup analyses showed that high GGT was positively associated with incident fatal events of chronic forms of coronary heart disease (P=0.009), congestive heart failure (P<0.001), and hemorrhagic (P=0.01) and ischemic stroke (P<0.001). No significant associations were observed for acute myocardial infarction (P=0.16). In women, hazard ratios suggested associations in all subgroups; however, for hemorrhagic and ischemic stroke they were not statistically significant (P=0.09 and P=0.07, respectively). In addition, subgroup analyses stratified by age revealed a stronger relationship of GGT in younger participants. Hazard ratios for total CVD were 2.03 (1.53 to 2.69) in men and 2.60 (1.53 to 4.42) in women younger than 60 years. CONCLUSIONS This study demonstrates in a large, prospectively observed cohort that GGT is independently associated with cardiovascular mortality.
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Affiliation(s)
- Elfriede Ruttmann
- Department of Medical Statistics, Informatics, and Health Economics, Innsbruck Medical University, Innsbruck, Austria
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36
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Corti A, Paolicchi A, Franzini M, Dominici S, Casini AF, Pompella A. The S-thiolating activity of membrane gamma-glutamyltransferase: formation of cysteinyl-glycine mixed disulfides with cellular proteins and in the cell microenvironment. Antioxid Redox Signal 2005; 7:911-8. [PMID: 15998246 DOI: 10.1089/ars.2005.7.911] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Previous studies have documented that activity of the plasma membrane enzyme gamma-glutamyltransferase (GGT) is accompanied by prooxidant processes, with production of reactive oxygen species and oxidation of cellular protein thiols. The present work was aimed to verify the occurrence and extent of S-thiolation mediated by GGT and characterize the molecular species involved in mixed disulfide formation. Experiments show that the cysteinyl-glycine (CG) originating from cellular GGT-mediated glutathione (GSH) metabolism can efficiently thiolate cellular proteins, as well as proteins present in the extracellular environment. With cells presenting high levels of GGT expression, basal levels of CG-containing protein mixed disulfides are detectable, in cellular proteins, as well as in proteins of the culture medium. Stimulation of GGT activity in these cells by administration of substrates results in an increase of CG mixed disulfide formation and a concomitant decrease of GSH-containing disulfides, likely due to GGT-dependent removal of GSH from the system. The findings reported suggest that binding of CG ("protein S-cysteylglycylation") may represent an as yet unrecognized function of membrane GGT, likely playing a regulatory role(s) in the cell and its surroundings.
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Affiliation(s)
- Alessandro Corti
- Department of Experimental Pathology BMIE, University of Pisa Medical School, Pisa, Italy
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Dominici S, Pieri L, Paolicchi A, De Tata V, Zunino F, Pompella A. Endogenous oxidative stress induces distinct redox forms of tumor necrosis factor receptor-1 in melanoma cells. Ann N Y Acad Sci 2005; 1030:62-8. [PMID: 15659781 DOI: 10.1196/annals.1329.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Receptors of the TNFR superfamily possess abundant thiols in their extracellular domains, which makes them susceptible to redox modulation by prooxidant agents and processes. Previous studies from our laboratory have documented that membrane gamma-glutamyltransferase (GGT) activity can originate reactive oxygen species in the extracellular milieu, during the GGT-mediated metabolism of extracellular glutathione. The present study was aimed thus to verify a possible redox-modulating effect of GGT activity on TNFR1 receptors. The thiol-specific probe maleimide-polyethylene glycol was used to selectively label the reduced thiol groups in proteins of cell lysates; fractions corresponding to TNFR1 were then identified by immunoblot. In human melanoma Me665/2 cells, expressing varying GGT levels, at least five distinct forms of TNFR1 have been thus identified. The more oxidized forms appear to be prevalent in the 2/60 clone, expressing higher GGT levels, as compared to clone 2/21. Stimulation of GGT activity in the latter induced an increase of the oxidized TNFR1 forms. It is conceivable that different redox states of TNFR1 may correspond to different binding affinity and/or changes in the transducing function of the receptor. As GGT is frequently expressed by malignant tumors, the described phenomena might concur to alter the sensitivity of cancer cells to agents targeted on activation of TNF-alpha-dependent signaling pathways.
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Affiliation(s)
- S Dominici
- Department of Experimental Pathology, University of Pisa Medical School, Via Roma 55, 56126 Pisa, Italy
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Pompella A, Emdin M, Passino C, Paolicchi A. The significance of serum gamma-glutamyltransferase in cardiovascular diseases. Clin Chem Lab Med 2005; 42:1085-91. [PMID: 15552264 DOI: 10.1515/cclm.2004.224] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since early after the introduction of serum gamma-glutamyltransferase (GGT) in clinical practice as a reliable and widely employed laboratory test, epidemiological and prospective studies have repeatedly shown that this activity possesses a prognostic value for morbidity and mortality. The association is independent of possibly concomitant conditions of liver disease, and notably, a significant independent correlation of serum GGT exists with the occurrence of cardiovascular diseases (myocardial infarction, stroke). Experimental work has documented that active GGT is present in atherosclerotic plaques of coronary as well as in cerebral arteries. These findings, and the recently recognized functions of GGT in the generation of reactive oxygen species, indicate that serum GGT represents a true marker of cardiovascular diseases and underlying atherosclerosis. Further insights into potential therapeutic interest will probably be derived from studies investigating the origin of GGT activity in plaque tissue.
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Affiliation(s)
- Alfonso Pompella
- Department of Experimental Pathology, University of Pisa Medical School, Pisa, Italy.
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Sahaf B, Heydari K, Herzenberg LA, Herzenberg LA. The extracellular microenvironment plays a key role in regulating the redox status of cell surface proteins in HIV-infected subjects. Arch Biochem Biophys 2005; 434:26-32. [PMID: 15629105 DOI: 10.1016/j.abb.2004.11.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Revised: 09/20/2004] [Indexed: 02/06/2023]
Abstract
There is an overwhelming interest in the study of the redox status of the cell surface affecting redox signaling in the cells and also predicting the total redox status of the cells. Measuring the total surface thiols (cell surface molecule thiols, csm-SH) we have shown that the overall level of surface thiols is tightly controlled. In vitro, the total concentration of intracellular glutathione (iGSH) seems to play a regulatory role in determination of the amounts of reduced proteins on cells. In addition, short term exposure of the cell surface to glutathione disulfide (GSSG, oxidized GSH) seems to reduce the overall levels of csm-SH suggesting that the function of some cysteine containing proteins on the cell surface may be regulated by the amount of GSSG secreted from the cells or the GSSG available in the extracellular environment. Examination of peripheral blood mononuclear cells (PBMCs) from healthy or HIV-infected subjects failed to reveal a similar correlation between the intra- and extracellular thiol status of cells. Although there is a relatively wide variation between individuals in both csm-SH and iGSH there is no correlation between the iGSH and csm-SH levels measured for healthy and HIV-infected individuals. There are many reports suggesting different redox active proteins on the cell surface to be the key players in the total cell surface redox regulation. However, we suggest that the redox status of the cells is regulated through a complex and tightly regulated mechanism that needs further investigation. In the mean time, overall surface thiol measurements together with case specific protein determinations may offer the most informative approach. In this review, we discuss our own results as well as results from other laboratories to argue that the overall levels of surface thiols on the exofacial membrane are regulated primarily by redox status of the cell surface microenvironment.
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Affiliation(s)
- Bita Sahaf
- Herzenberg Laboratory, Department of Genetics, Beckman Center, B-007 Stanford University School of Medicine Stanford, CA 94304-5318, USA.
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40
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Corti A, Raggi C, Franzini M, Paolicchi A, Pompella A, Casini AF. Plasma membrane gamma-glutamyltransferase activity facilitates the uptake of vitamin C in melanoma cells. Free Radic Biol Med 2004; 37:1906-15. [PMID: 15528049 DOI: 10.1016/j.freeradbiomed.2004.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Revised: 08/03/2004] [Accepted: 08/26/2004] [Indexed: 11/26/2022]
Abstract
Adequate cellular transport of ascorbic acid (AA) and its oxidation product dehydroascorbate (DHA) is assured through specific carriers. It was shown that vitamin C is taken up as DHA by most cell types, including cancer cells, via the facilitative GLUT transporters. Thus, AA oxidation to DHA can be considered a mechanism favoring vitamin C uptake and intracellular accumulation. We have investigated whether such an AA-oxidizing action might be provided by plasma membrane gamma-glutamyltransferase (GGT), previously shown to function as an autocrine source of prooxidants. The process was studied using two distinct human metastatic melanoma clones. It was observed that the Me665/2/60 clone, expressing high levels of membrane GGT activity, was capable of effecting the oxidation of extracellular AA, accompanied by a marked increase of intracellular AA levels. The phenomenon was not observed with Me665/2/21 cells, possessing only traces of membrane GGT. On the other hand, AA oxidation and stimulation of cellular uptake were indeed observed after transfection of 2/21 cells with cDNA coding for GGT. The mechanism of GGT-mediated AA oxidation was investigated in acellular systems, including GGT and its substrate glutathione. The process was observed in the presence of redox-active chelated iron(II) and of transferrin or ferritin, i.e., two physiological iron sources. Thus, membrane GGT activity-often expressed at high levels in human malignancies-can oxidize extracellular AA and promote its uptake efficiently.
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Affiliation(s)
- Alessandro Corti
- Department of Experimental Pathology B.M.I.E., University of Pisa Medical School, Via Roma 55, 56126 Pisa, Italy
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Abstract
The primary role of cellular gamma glutamyltransferase (GGT) is to metabolize extracellular reduced glutathione (GSH), allowing for precursor amino acids to be assimilated and reutilized for intracellular GSH synthesis. Paradoxically, recent experimental studies indicate that cellular GGT may also be involved in the generation of reactive oxygen species in the presence of iron or other transition metals. Although the relationship between cellular GGT and serum GGT is not known and serum GGT activity has been commonly used as a marker for excessive alcohol consumption or liver diseases, our series of epidemiological studies consistently suggest that serum GGT within its normal range might be an early and sensitive enzyme related to oxidative stress. For example, serum and dietary antioxidant vitamins had inverse, dose-response relations to serum GGT level within its normal range, whereas dietary heme iron was positively related to serum GGT level. More importantly, serum GGT level within its normal range positively predicted F2-isoprostanes, an oxidative damage product of arachidonic acid, and fibrinogen and C-reactive protein, markers of inflammation, which were measured 5 or 15 years later, in dose-response manners. These findings suggest that strong associations of serum GGT with many cardiovascular risk factors and/or events might be explained by a mechanism related to oxidative stress. Even though studies on serum and/or cellular GGT is at a beginning stage, our epidemiological findings suggest that serum GGT might be useful in studying oxidative stress-related issues in both epidemiological and clinical settings.
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Affiliation(s)
- Duk-Hee Lee
- Department of Preventive Medicine and Health Promotion Research Center, School of Medicine, Kyungpook National University, Daegu, South Korea.
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42
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Busiello I, Acquaviva R, Di Popolo A, Blanchard TG, Ricci V, Romano M, Zarrilli R. Helicobacter pylori gamma-glutamyltranspeptidase upregulates COX-2 and EGF-related peptide expression in human gastric cells. Cell Microbiol 2004; 6:255-67. [PMID: 14764109 DOI: 10.1046/j.1462-5822.2004.00366.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gastric mucosa responds to Helicobacter pylori-induced cell damage by increasing the expression of COX-2 and EGF-related peptides. We sought to investigate the bacterial virulence factor/s and the host cellular pathways involved in the upregulation of COX-2, HB-EGF and amphiregulin in MKN 28 and AGS gastric mucosal cells. H. pylori strain CCUG 17874 was grown in Brucella broth supplemented with 0.2% (2,6-dimethyl)-beta-cyclodextrins. The soluble proteins released in the culture medium by the bacterium were fractionated by exclusion size and anion exchange chromatography. A single peak retaining the ability to upregulate COX-2 and HB-EGF mRNA and protein expression was obtained. SDS-PAGE analysis of the peak showed two peptides with an apparent molecular weight of 38 and 22 kDa, which were identified by automated Edman degradation analysis as the N-terminal and C-terminal peptides of H. pylori gamma-glutamyltranspeptidase respectively. Acivicin, a selective gamma-glutamyltranspeptidase inhibitor, counteracted H. pylori-induced upregulation of COX-2 and EGF-related peptide mRNA expression. An H. pylori isogenic mutant gamma-glutamyltranspeptidase-deficient strain did not exert any effect on COX-2, HB-EGF and amphiregulin mRNA expression. Blockade of phosphatidylinositol-3 kinase and p38 kinase, but not MAP kinase kinase, inhibited H. pylori gamma-glutamyltranspeptidase-induced upregulation of COX-2 and EGF-related peptide mRNA expression.
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Affiliation(s)
- Immacolata Busiello
- Dipartimento di Biologia e Patologia Cellulare e Molecolare 'L. Califano', Universitá di Napoli 'Frederico II', Napoli, Italy
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Ruoso P, Hedley DW. Inhibition of gamma-glutamyl transpeptidase activity decreases intracellular cysteine levels in cervical carcinoma. Cancer Chemother Pharmacol 2004; 54:49-56. [PMID: 15034755 DOI: 10.1007/s00280-004-0776-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Accepted: 01/21/2004] [Indexed: 10/26/2022]
Abstract
PURPOSE To determine whether gamma-glutamyl transpeptidase (gamma-GT) is involved in the maintenance of elevated cysteine levels in cervical carcinoma. METHODS Four cervical carcinoma cell lines were tested in vitro for cysteine accumulation and gamma-GT levels. The highest and lowest gamma-GT-expressing cell lines were used in in vivo experiments to determine the effect of gamma-GT inhibition on cysteine levels. RESULTS Treatment of a series of cervical carcinoma cell lines with acivicin decreased intracellular cysteine concentrations. Cysteine depletion was evident in Me180 cells which had the greatest levels of gamma-GT activity, and had a more pronounced cysteine decrease in medium with glutathione and cysteine concentrations simulating the in vivo situation. Also investigated were the effects of inhibition of gamma-GT activity on intracellular cysteine levels in xenografts grown in severe combined immunodeficient (SCID) mice. With the use of 35 mg/kg of acivicin, gamma-GT activity decreased to basal levels of detection in both tumour types and significant decreases in cysteine levels were seen in the high gamma-GT-expressing tumours (Me180). Thus, inhibition of gamma-GT activity may have therapeutic potential in high-expressing cancers. CONCLUSIONS In tumours and cell lines with elevated levels of gamma-GT activity, inhibition of this enzyme led to decreases of cysteine levels.
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Affiliation(s)
- P Ruoso
- Division of Experimental Therapeutics, Department of Medical Biophysics, Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada
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44
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Dominici S, Paolicchi A, Lorenzini E, Maellaro E, Comporti M, Pieri L, Minotti G, Pompella A. Gamma-glutamyltransferase-dependent prooxidant reactions: a factor in multiple processes. Biofactors 2003; 17:187-98. [PMID: 12897440 DOI: 10.1002/biof.5520170118] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Silvia Dominici
- Department of Experimental Pathology, University of Pisa Medical School, Pisa, Italy
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45
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Enoiu M, Herber R, Leroy P, Wellman M. The role of gamma-glutamyltranspeptidase in the metabolism and cytotoxicity of 4-hydroxynonenal-glutathione conjugate: evidence and hypothesis. Biofactors 2003; 17:175-85. [PMID: 12897439 DOI: 10.1002/biof.5520170117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Milica Enoiu
- Faculty of Pharmacy, University Carol Davila, 6 Traian Vuia, 70139 Bucharest, Romania
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46
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Chaubal VA, Nair SS, Ito S, Wakamatsu K, Mojamdar MV. Gamma-glutamyl transpeptidase and its role in melanogenesis: redox reactions and regulation of tyrosinase. PIGMENT CELL RESEARCH 2002; 15:420-5. [PMID: 12453183 DOI: 10.1034/j.1600-0749.2002.02004.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Metabolism of glutathione by gamma-glutamyl transpeptidase (gamma-GT) at the level of cell membrane has been shown to generate hydrogen peroxide in many cell types including human melanomas. gamma-GT does not appear to be involved in cysteine uptake for pheomelanin production in melanoma cells and does not contribute significantly to the pheomelanin synthesized in B16 melanoma cells. We have therefore examined the possibility of gamma-GT mediated production of prooxidant reactions and its effect, if any, on pigmentation using B16 melanoma cells. Our results indicate that in B16 melanoma cells, gamma-GT activity leads to the production of hydrogen peroxide. We further show that the nuclear levels of the redox sensitive transcription factor NF-kappa B is regulated by H2O2 formed by the action of gamma-GT: stimulation and inhibition of gamma-GT affect the levels of NF-kappa B. Tumor necrosis factor alpha, a hypopigmenting cytokine, known to activate NF-kappa B also up-regulates the gamma-GT messenger RNA and activity. Stimulation of gamma-GT generated prooxidant reactions led to a decrease in tyrosinase activity. We therefore propose that prooxidant reactions mediated by gamma-GT in turn regulate the levels of tyrosinase in pigment cells. Our findings thus introduce a new aspect in the regulation of pigmentation and ascribe a novel role for gamma-GT in pigment cells.
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Affiliation(s)
- Vaishali A Chaubal
- National Centre for Cell Science, NCCS Complex, Pune University Campus, Ganeshkhind, Pune, Maharashtra,
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Paolicchi A, Dominici S, Pieri L, Maellaro E, Pompella A. Glutathione catabolism as a signaling mechanism. Biochem Pharmacol 2002; 64:1027-35. [PMID: 12213602 DOI: 10.1016/s0006-2952(02)01173-5] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Glutathione (GSH) is the main intracellular thiol antioxidant, and as such participates in a number of cellular antitoxic and defensive functions. Nevertheless, non-antioxidant functions of GSH have also been described, e.g. in modulation of cell proliferation and immune response. Recent studies from our and other laboratories have provided evidence for a third functional aspect of GSH, i.e. the prooxidant roles played by molecular species originating during its catabolism by the membrane ectoenzyme gamma-glutamyl transpeptidase (GGT). The reduction of metal ions effected by GSH catabolites is capable to induce redox cycling processes leading to the production of reactive oxygen species (superoxide, hydrogen peroxide), as well as of other free radicals. Through the action of these reactive compounds, GSH catabolism can ultimately lead to oxidative modifications on a variety of molecular targets, involving oxidation and/or S-thiolation of protein thiol groups in the first place. Modulating effects of this kind have been observed on several important, redox-sensitive components of the signal transduction chains, such as cell surface receptors, protein phosphatase activities and transcription factors. Against this background, the prooxidant reactions induced by GSH catabolism appear to represent a novel, as yet unrecognized mechanism for modulation of cellular signal transduction.
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Affiliation(s)
- Aldo Paolicchi
- Department of Experimental Pathology, University of Pisa Medical School, Via Roma 55, 56126 Pisa, Italy
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Firla B, Arndt M, Frank K, Thiel U, Ansorge S, Täger M, Lendeckel U. Extracellular cysteines define ectopeptidase (APN, CD13) expression and function. Free Radic Biol Med 2002; 32:584-95. [PMID: 11909693 PMCID: PMC7126538 DOI: 10.1016/s0891-5849(01)00827-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alanyl aminopeptidase (APN) is a surface-bound metallopeptidase that processes the N-terminals of biologically active peptides such as enkephalins, angiotensins, neurokinins, and cytokines. It exerts profound activity on vital processes such as immune response, cellular growth, and blood pressure control. Inhibition of either APN gene expression or its enzymatic activity severely affects leukocyte growth and function. We show here that oxidoreductase-mediated modulations of the cell surface thiol status affect the enzymatic activity of APN. Additional evidence for the pivotal role of extracellular cysteines in the APN molecule was obtained when substitution of any of these six cysteines caused complete loss of surface expression and enzymatic activity. In contrast, the transmembrane Cys24 appears to have no similar function. Enzymatically inactive cysteine mutants were retained in the endoplasmic reticulum as shown by high-resolution imaging and Endoglycosidase H digestion. In the absence of any crystal-structure data, the demonstration that individual extracellular cysteines contribute to APN expression and function appears to be of particular importance. The data are the first to show thiol-dependent modulation of the activity of a typical surface-bound peptidase at the cell surface, probably reflecting a general regulating mechanism. This may relate to various disease processes such as inflammation or malignant transformation.
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Key Words
- aminopeptidase n
- proteindisulfide isomerase
- thiol status
- disulfide bond
- site-directed mutagenesis
- free radicals
- ala-pna, alanylparanitroanilide
- apn, aminopeptidase n
- b-all, acute b cell leukemia
- bsa, bovine serum albumin
- bso, buthionine sulfoximine
- cd, cluster of differentiation
- cml, chronic myeloid leukemia
- cmv, cytomegalovirus
- er, endoplasmic reticulum
- facs, fluorescence-activated cell sorting
- fcs, fetal calf serum
- gfp, green fluorescent protein
- hrp, horseradish peroxidase
- mfi, mean fluorescence intensity
- nem, n-ethylmaleimide
- nhl, non-hodgkin lymphoma
- page, polyacrylamide gel electrophoresis
- pbs, phosphate-buffered saline
- pe, phycoerythrin
- pngase f, peptide n-glycosidase f
- sds, sodiumdodecylsulfate
- trh-de, thyrotropin-releasing hormone-degrading ectoenzyme
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Affiliation(s)
- Beate Firla
- Institute of Immunology, Otto-von-Guericke-University of Magdeburg, Magdeburg, Germany.
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Paolicchi A, Lorenzini E, Perego P, Supino R, Zunino F, Comporti M, Pompella A. Extra-cellular thiol metabolism in clones of human metastatic melanoma with different gamma-glutamyl transpeptidase expression: implications for cell response to platinum-based drugs. Int J Cancer 2002; 97:740-5. [PMID: 11857348 DOI: 10.1002/ijc.10110] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Thiol redox status can affect important functions both intracellularly and extracellularly. The plasma membrane enzyme gamma-glutamyl transpeptidase (GGT), which plays a crucial role in cellular handling of thiols, is often expressed in malignant tumors, including melanoma, although its expression levels may vary widely among different tumors or cells of the same tumor. In an attempt to better understand the functional significance of GGT overexpression, we have examined the relationships between intra- and extra-cellular thiol metabolism and GGT expression. Intra- and extra-cellular distribution of glutathione and other low mol. wt. thiols and disulfides was investigated in two different Me665/2 human melanoma clones that originated from the same metastasis, but exhibiting high (2/60 clone) and low (2/21 clone) GGT activity. Intracellular content of glutathione was lower in GGT-rich 2/60 cells, in spite of high GGT expression. A lower utilization of extracellular cystine was also observed in these cells. In both clones, a direct secretion of cysteine in the extracellular medium was detected, which was independent of GGT-mediated catabolism of extracellular glutathione. Substantial amounts of glutathione, GSSG and glutathione-cysteine disulfide were accumulated extracellularly only in the case of GGT-poor 2/21 cells, while the same event was apparent in 2/60 cells only after the following inhibition of GGT activity. When exposed to the trinuclear platinum compound BBR 3464 or hydrogen peroxide, which are very reactive for sulfur-containing nucleophiles, the 2/60 clone showed higher sensitivity than the 2/21 clone to both agents. These results suggest that the clone-specific balance between transport of sulfur aminoacids and GGT activity results in profound differences in the capability of each clone to modify the thiol redox status of the extracellular milieu. The finding may have important implications in tumor cell behavior with particular reference to chemosensitivity, since thiols are recognized factors in modulation of cell sensitivity to platinum-based anticancer drugs.
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Affiliation(s)
- Aldo Paolicchi
- Department of Experimental Pathology and Medical Biotechnologies, University of Pisa, Italy
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Hua Long L, Halliwell B. Oxidation and generation of hydrogen peroxide by thiol compounds in commonly used cell culture media. Biochem Biophys Res Commun 2001; 286:991-4. [PMID: 11527398 DOI: 10.1006/bbrc.2001.5514] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Many studies have examined the effects of thiol compounds upon cells in culture (e.g., upon signal transduction and regulation of gene expression), but few have considered how thiols can interact with cell culture media. A wide range of thiols (cysteine, GSH, N-acetylcysteine, gamma-glutamylcysteine, cysteinylglycine, cysteamine, homocysteine) were found to interact with three commonly used cell culture media (RPMI, MEM, DMEM) to generate hydrogen peroxide with complex concentration-dependencies. Thiols added to these media rapidly disappeared, although less H(2)O(2) was generated on a molar basis than the amount of thiol lost. Studies on cellular effects of thiols, especially those on redox regulation of gene expression or protein function, need to take into account that thiols are rapidly lost, and that their oxidation generates H(2)O(2), which can have multiple concentration-dependent effects on cell metabolism.
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Affiliation(s)
- L Hua Long
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, Medical Drive, MD7 03-15, 10 Kent Ridge Crescent, Singapore, 119260
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