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Shi Z, Hu C, Zheng X, Sun C, Li Q. Feedback loop between hypoxia and energy metabolic reprogramming aggravates the radioresistance of cancer cells. Exp Hematol Oncol 2024; 13:55. [PMID: 38778409 PMCID: PMC11110349 DOI: 10.1186/s40164-024-00519-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
Radiotherapy is one of the mainstream approaches for cancer treatment, although the clinical outcomes are limited due to the radioresistance of tumor cells. Hypoxia and metabolic reprogramming are the hallmarks of tumor initiation and progression and are closely linked to radioresistance. Inside a tumor, the rate of angiogenesis lags behind cell proliferation, and the underdevelopment and abnormal functions of blood vessels in some loci result in oxygen deficiency in cancer cells, i.e., hypoxia. This prevents radiation from effectively eliminating the hypoxic cancer cells. Cancer cells switch to glycolysis as the main source of energy, a phenomenon known as the Warburg effect, to sustain their rapid proliferation rates. Therefore, pathways involved in metabolic reprogramming and hypoxia-induced radioresistance are promising intervention targets for cancer treatment. In this review, we discussed the mechanisms and pathways underlying radioresistance due to hypoxia and metabolic reprogramming in detail, including DNA repair, role of cancer stem cells, oxidative stress relief, autophagy regulation, angiogenesis and immune escape. In addition, we proposed the existence of a feedback loop between energy metabolic reprogramming and hypoxia, which is associated with the development and exacerbation of radioresistance in tumors. Simultaneous blockade of this feedback loop and other tumor-specific targets can be an effective approach to overcome radioresistance of cancer cells. This comprehensive overview provides new insights into the mechanisms underlying tumor radiosensitivity and progression.
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Affiliation(s)
- Zheng Shi
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Cuilan Hu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiaogang Zheng
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chao Sun
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.
- Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - Qiang Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.
- Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou, China.
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China.
- University of Chinese Academy of Sciences, Beijing, China.
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Abdelrahman S, Alghrably M, Campagna M, Hauser CAE, Jaremko M, Lachowicz JI. Metal Complex Formation and Anticancer Activity of Cu(I) and Cu(II) Complexes with Metformin. Molecules 2021; 26:molecules26164730. [PMID: 34443319 PMCID: PMC8401132 DOI: 10.3390/molecules26164730] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 01/13/2023] Open
Abstract
Metformin has been used for decades in millions of type 2 diabetes mellitus patients. In this time, correlations between metformin use and the occurrence of other disorders have been noted, as well as unpredictable metformin side effects. Diabetes is a significant cancer risk factor, but unexpectedly, metformin-treated diabetic patients have lower cancer incidence. Here, we show that metformin forms stable complexes with copper (II) ions. Both copper(I)/metformin and copper(II)/metformin complexes form adducts with glutathione, the main intracellular antioxidative peptide, found at high levels in cancer cells. Metformin reduces cell number and viability in SW1222 and K562 cells, as well as in K562-200 multidrug-resistant cells. Notably, the antiproliferative effect of metformin is enhanced in the presence of copper ions.
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Affiliation(s)
- Sherin Abdelrahman
- Laboratory for Nanomedicine, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
| | - Mawadda Alghrably
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia;
| | - Marcello Campagna
- Department of Medical Sciences and Public Health, University of Cagliari, Policlinico Universitario, 09124 Cagliari, Italy;
| | - Charlotte Armgard Emma Hauser
- Laboratory for Nanomedicine, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
- Correspondence: (C.A.E.H.); (M.J.); (J.I.L.)
| | - Mariusz Jaremko
- Laboratory for Nanomedicine, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
- Correspondence: (C.A.E.H.); (M.J.); (J.I.L.)
| | - Joanna Izabela Lachowicz
- Department of Medical Sciences and Public Health, University of Cagliari, Policlinico Universitario, 09124 Cagliari, Italy;
- Correspondence: (C.A.E.H.); (M.J.); (J.I.L.)
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Oxidative Stress-Inducing Anticancer Therapies: Taking a Closer Look at Their Immunomodulating Effects. Antioxidants (Basel) 2020; 9:antiox9121188. [PMID: 33260826 PMCID: PMC7759788 DOI: 10.3390/antiox9121188] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/19/2020] [Accepted: 11/25/2020] [Indexed: 02/06/2023] Open
Abstract
Cancer cells are characterized by higher levels of reactive oxygen species (ROS) compared to normal cells as a result of an imbalance between oxidants and antioxidants. However, cancer cells maintain their redox balance due to their high antioxidant capacity. Recently, a high level of oxidative stress is considered a novel target for anticancer therapy. This can be induced by increasing exogenous ROS and/or inhibiting the endogenous protective antioxidant system. Additionally, the immune system has been shown to be a significant ally in the fight against cancer. Since ROS levels are important to modulate the antitumor immune response, it is essential to consider the effects of oxidative stress-inducing treatments on this response. In this review, we provide an overview of the mechanistic cellular responses of cancer cells towards exogenous and endogenous ROS-inducing treatments, as well as the indirect and direct antitumoral immune effects, which can be both immunostimulatory and/or immunosuppressive. For future perspectives, there is a clear need for comprehensive investigations of different oxidative stress-inducing treatment strategies and their specific immunomodulating effects, since the effects cannot be generalized over different treatment modalities. It is essential to elucidate all these underlying immune effects to make oxidative stress-inducing treatments effective anticancer therapy.
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Wang H, Jiang H, Van De Gucht M, De Ridder M. Hypoxic Radioresistance: Can ROS Be the Key to Overcome It? Cancers (Basel) 2019; 11:cancers11010112. [PMID: 30669417 PMCID: PMC6357097 DOI: 10.3390/cancers11010112] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/11/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Radiotherapy is a mainstay treatment for many types of cancer and kills cancer cells via generation of reactive oxygen species (ROS). Incorporating radiation with pharmacological ROS inducers, therefore, has been widely investigated as an approach to enhance aerobic radiosensitization. However, this strategy was overlooked in hypoxic counterpart, one of the most important causes of radiotherapy failure, due to the notion that hypoxic cells are immune to ROS insults because of the shortage of ROS substrate oxygen. Paradoxically, evidence reveals that ROS are produced more in hypoxic than normoxic cells and serve as signaling molecules that render cells adaptive to hypoxia. As a result, hypoxic tumor cells heavily rely on antioxidant systems to sustain the ROS homeostasis. Thereby, they become sensitive to insults that impair the ROS detoxification network, which has been verified in diverse models with or without radiation. Of note, hypoxic radioresistance has been overviewed in different contexts. To the best of our knowledge, this review is the first to systemically summarize the interplay among radiation, hypoxia, and ROS, and to discuss whether perturbation of ROS homeostasis could provide a new avenue to tackle hypoxic radioresistance.
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Affiliation(s)
- Hui Wang
- Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
| | - Heng Jiang
- Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
| | - Melissa Van De Gucht
- Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
| | - Mark De Ridder
- Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
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Vučetić M, Cormerais Y, Parks SK, Pouysségur J. The Central Role of Amino Acids in Cancer Redox Homeostasis: Vulnerability Points of the Cancer Redox Code. Front Oncol 2017; 7:319. [PMID: 29312889 PMCID: PMC5742588 DOI: 10.3389/fonc.2017.00319] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022] Open
Abstract
A fine balance in reactive oxygen species (ROS) production and removal is of utmost importance for homeostasis of all cells and especially in highly proliferating cells that encounter increased ROS production due to enhanced metabolism. Consequently, increased production of these highly reactive molecules requires coupling with increased antioxidant defense production within cells. This coupling is observed in cancer cells that allocate significant energy reserves to maintain their intracellular redox balance. Glutathione (GSH), as a first line of defense, represents the most important, non-enzymatic antioxidant component together with the NADPH/NADP+ couple, which ensures the maintenance of the pool of reduced GSH. In this review, the central role of amino acids (AAs) in the maintenance of redox homeostasis in cancer, through GSH synthesis (cysteine, glutamate, and glycine), and nicotinamide adenine dinucleotide (phosphate) production (serine, and glutamine/glutamate) are illustrated. Special emphasis is placed on the importance of AA transporters known to be upregulated in cancers (such as system xc-light chain and alanine-serine-cysteine transporter 2) in the maintenance of AA homeostasis, and thus indirectly, the redox homeostasis of cancer cells. The role of the ROS varies (often described as a "two-edged sword") during the processes of carcinogenesis, metastasis, and cancer treatment. Therefore, the context-dependent role of specific AAs in the initiation, progression, and dissemination of cancer, as well as in the redox-dependent sensitivity/resistance of the neoplastic cells to chemotherapy are highlighted.
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Affiliation(s)
- Milica Vučetić
- Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco, Monaco
| | - Yann Cormerais
- Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco, Monaco
| | - Scott K Parks
- Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco, Monaco
| | - Jacques Pouysségur
- Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco, Monaco.,Institute for Research on Cancer and Aging (IRCAN), CNRS, INSERM, Centre A. Lacassagne, Université Côte d'Azur, Nice, France
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Medriano CAD, Na J, Lim KM, Chung JH, Park YH. Liquid Chromatography Mass Spectrometry-Based Metabolite Pathway Analyses of Myeloma and Non-Hodgkin's Lymphoma Patients. CELL JOURNAL 2017; 19:44-54. [PMID: 28580307 PMCID: PMC5448325 DOI: 10.22074/cellj.2017.4412] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/28/2016] [Indexed: 11/29/2022]
Abstract
Objective This study attempted to identify altered metabolism and pathways related to
non-Hodgkin’s lymphoma (NHL) and myeloma patients.
Materials and Methods In this retrospective study, we collected plasma samples from
11 patients-6 healthy controls with no evidence of any blood cancers and 5 patients with
either multiple myeloma (n=3) or NHL (n=2) during the preliminary study period. Samples
were analyzed using quadrupole time-of-flight liquid chromatography mass spectrometry
(LC-MS). Significant features generated after statistical analyses were used for metabolomics and pathway analysis. Results Data after false discovery rate (FDR) adjustment at q=0.05 of features showed
136 for positive and 350 significant features for negative ionization mode in NHL patients as
well as 262 for positive and 98 features for negative ionization mode in myeloma patients.
Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis determined that
pathways such as steroid hormone biosynthesis, ABC transporters, and arginine and proline
metabolism were affected in NHL patients. In myeloma patients, pyrimidine metabolism,
carbon metabolism, and bile secretion pathways were potentially affected by the disease. Conclusion The results have shown tremendous differences in the metabolites of healthy
individuals compared to myeloma and lymphoma patients. Validation through quantitative
metabolomics is encouraged, especially for the metabolites with significantly expression
in blood cancer patients.
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Affiliation(s)
| | - Jinhyuk Na
- Metabolomics Laboratory, College of Pharmacy, Korea University, Sejong City, Korea
| | - Kyung-Min Lim
- College of Pharmacy, Ewha Woman's University, Seoul, Korea
| | - Jin-Ho Chung
- College of Pharmacy, Seoul National University, Seoul, Korea
| | - Youngja H Park
- Metabolomics Laboratory, College of Pharmacy, Korea University, Sejong City, Korea
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KIM AREUMDASEUL, ZHANG RUI, HAN XIA, KANG KYOUNGAH, PIAO MEIJING, MAENG YOUNGHEE, CHANG WEONYOUNG, HYUN JINWON. Involvement of glutathione and glutathione metabolizing enzymes in human colorectal cancer cell lines and tissues. Mol Med Rep 2015; 12:4314-4319. [DOI: 10.3892/mmr.2015.3902] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/30/2015] [Indexed: 11/06/2022] Open
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QI RONGXIN, JIN WENWEN, WANG JUAN, YI QIYI, YU MAOHU, XU SHIGUO, JIN WENSEN. Oleanolic acid enhances the radiosensitivity of tumor cells under mimetic hypoxia through the reduction in intracellular GSH content and HIF-1α expression. Oncol Rep 2014; 31:2399-406. [DOI: 10.3892/or.2014.3064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 02/21/2014] [Indexed: 11/06/2022] Open
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Opposing influence of intracellular and membrane thiols on the toxicity of reducible polycations. Biomaterials 2013; 34:8843-50. [PMID: 23948163 DOI: 10.1016/j.biomaterials.2013.07.095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 07/29/2013] [Indexed: 11/23/2022]
Abstract
Toxicity of polycations has been recognized since their first use in gene delivery. Bioreducible polycations attract attention because of their improved safety due to selective intracellular degradation by glutathione (GSH). Here we present a systematic study of the toxicity of bioreducible poly(amido amine)s (PAA). PAA with increasing content of disulfide bonds were synthesized by Michael addition. Toxicity of PAA was evaluated in two cell lines with different innate levels of intracellular GSH. Increasing the content of disulfide bonds decreased the toxicity of PAA, with more significant decrease observed in cells with high GSH. Depleting intracellular GSH by diethyl maleate resulted in increased toxicity of bioreducible PAA. In contrast, increasing the GSH concentrations by growing cells in hypoxic conditions resulted in further decreased toxicity compared with cells grown in normoxic conditions. The presence of exofacial plasma membrane thiols selectively increased toxicity of bioreducible PAA while having no effect on non-degradable controls. These results improve our understanding of the cellular mechanisms of polycation toxicity. They also shed light on the opposing effects of different cellular thiol pools on the toxicity of bioreducible polycations.
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Tumor Xenograft Response to Redox-Active Therapies Assessed by Magnetic Resonance Imaging Using a Thiol-Bearing DOTA Complex of Gadolinium. Transl Oncol 2012; 5:190-9. [PMID: 22741038 DOI: 10.1593/tlo.11322] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 11/01/2011] [Accepted: 02/14/2012] [Indexed: 11/18/2022] Open
Abstract
Gd-LC6-SH is a thiol-bearing DOTA complex of gadolinium designed to bind plasma albumin at the conserved Cys(34) site. The binding of Gd-LC6-SH shows sensitivity to the presence of competing thiols. We hypothesized that Gd-LC6-SH could provide magnetic resonance imaging (MRI) enhancement that is sensitive to tumor redox state and that the prolonged retention of albumin-bound Gd-LC6-SH in vivo can be exploited to identify a saturating dose above which the shortening of MRI longitudinal relaxation time (T(1)) of tissue is insensitive to the injected gadolinium dose. In the Mia-PaCa-2 pancreatic tumor xenograft model in SCID mice, both the small-molecule Gd-DTPA-BMA and the macromolecule Galbumin MRI contrast agents produced dose-dependent decreases in tumor T(1). By contrast, the decreases in tumor T(1) provided by Gd-LC6-SH at 0.05 and 0.1 mmol/kg were not significantly different at longer times after injection. SCID mice bearing Mia-PaCa-2 or NCI-N87 tumor xenografts were treated with either the glutathione synthesis inhibitor buthionine sulfoximine or the thiol-oxidizing anticancer drug Imexon, respectively. In both models, there was a significantly greater increase in tumor R(1) (=1/T(1)) 60 minutes after injection of Gd-LC6-SH in drug-treated animals relative to saline-treated controls. In addition, Mercury Orange staining for nonprotein sulfhydryls was significantly decreased by drug treatment relative to controls in both tumor models. In summary, these studies show that thiol-bearing complexes of gadolinium such as Gd-LC6-SH can serve as redox-sensitive MRI contrast agents for detecting differences in tumor redox status and can be used to evaluate the effects of redox-active drugs.
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Pham NA, Magalhaes JMMM, Do T, Schwock J, Dhani N, Cao PJ, Hill RP, Hedley DW. Activation of Src and Src-associated signaling pathways in relation to hypoxia in human cancer xenograft models. Int J Cancer 2009; 124:280-6. [PMID: 18924149 DOI: 10.1002/ijc.23912] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The hypoxic response in vitro involves alterations in signaling proteins, including Src, STAT3 and AKT that are considered to be broadly pro-survival. The involvement of these signaling proteins in the hypoxic microenviroments that occur in solid tumors was investigated by the use of multicolor fluorescence image analysis to colocalize signaling proteins and regions of hypoxia in 4 human tumor xenografts, pancreatic carcinoma BxPC3 and PANC1 and cervical squamous cell carcinoma ME180 and SiHa. Expression levels of total Src protein (mean intensity x labeled region fraction) were higher in hypoxic regions, identified using the nitroimidazole probe EF5, relative to non-EF5 regions in all 4 tumor models. This was associated with higher levels of phosphorylated (p-) Y419p-Src and its substrate Y861p-FAK in EF5 positive regions of BxPC3 tumors. This effect was also seen in tumor-bearing mice continuously breathing 7% oxygen for 3 hr which markedly increased the extent of EF5 positive labeling. In contrast, the hypoxia treatment resulted in a significant decrease in S727p-STAT3 in BxPC3 xenografts and suggested that STAT3 activity is responsive to acute hypoxia, whereas Src-FAK signaling is associated with predominantly chronically hypoxic EF5 positive regions. Src activity in both hypoxic and nonhypoxic BxPC3 tumor regions was suppressed when mice were treated with the Src inhibitor AZD0530 (25 mg/kg/day, 5 days), suggesting that both hypoxic and normoxic tumor regions are accessible to pharmacological Src inhibition. These results show that signaling pathways are responsive to tumor hypoxia in vivo, although the effects appear to differ between individual tumor types.
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Affiliation(s)
- Nhu-An Pham
- Ontario Cancer Institute, Princess Margaret Hospital, and Department of Laboratory Medicine and Pathology, University of Toronto, Toronto, Ontario, Canada
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Wardman P. Chemical radiosensitizers for use in radiotherapy. Clin Oncol (R Coll Radiol) 2007; 19:397-417. [PMID: 17478086 DOI: 10.1016/j.clon.2007.03.010] [Citation(s) in RCA: 307] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 03/13/2007] [Indexed: 12/21/2022]
Abstract
Radiosensitizers are intended to enhance tumour cell killing while having much less effect on normal tissues. Some drugs target different physiological characteristics of the tumour, particularly hypoxia associated with radioresistance. Oxygen is the definitive hypoxic cell radiosensitizer, the large differential radiosensitivity of oxic vs hypoxic cells being an attractive factor. The combination of nicotinamide to reduce acute hypoxia with normobaric carbogen breathing is showing clinical promise. 'Electron-affinic' chemicals that react with DNA free radicals have the potential for universal activity to combat hypoxia-associated radioresistance; a nitroimidazole, nimorazole, is clinically effective at tolerable doses. Hypoxia-specific cytotoxins, such as tirapazamine, are valuable adjuncts to radiotherapy. Nitric oxide is a potent hypoxic cell radiosensitizer; variations in endogenous levels might have prognostic significance, and routes to deliver nitric oxide specifically to tumours are being developed. In principle, many drugs can be delivered selectively to hypoxic tumours using either reductase enzymes or radiation-produced free radicals to activate drug release from electron-affinic prodrugs. A redox-active agent based on a gadolinium chelate is being evaluated clinically. Pyrimidines substituted with bromine or iodine are incorporated into DNA and enhance free radical damage; fluoropyrimidines act by different mechanisms. A wide variety of drugs that influence the nature or repair of DNA damage are being evaluated in conjunction with radiation; it is often difficult to define the mechanisms underlying chemoradiation regimens. Drugs being evaluated include topoisomerase inhibitors (e.g. camptothecin, topotecan), and the hypoxia-activated anthraquinone AQ4N; alkylating agents include temozolomide. Drugs involved in DNA repair pathways being investigated include the potent poly(ADP ribose)polymerase inhibitor, AG14,361. Proteins involved in cell signalling, such as the Ras family, are attractive targets linked to radioresistance, as are epidermal growth factor receptors and linked kinases (drugs including vandetanib [ZD6,474], cetuximab and gefitinib), and cyclooxygenase-2 (celecoxib). The suppression of radioprotective thiols seems to offer more potential with alkylating agents than with radiotherapy, although it remains a strategy worthy of exploration.
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Affiliation(s)
- P Wardman
- University of Oxford, Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood HA6 2JR, UK.
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13
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Meurette O, Lefeuvre-Orfila L, Rebillard A, Lagadic-Gossmann D, Dimanche-Boitrel MT. Role of intracellular glutathione in cell sensitivity to the apoptosis induced by tumor necrosis factor {alpha}-related apoptosis-inducing ligand/anticancer drug combinations. Clin Cancer Res 2005; 11:3075-83. [PMID: 15837763 DOI: 10.1158/1078-0432.ccr-04-1764] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We have recently shown that combination of tumor necrosis factor alpha-related apoptosis-inducing ligand (TRAIL) with anticancer drugs induced an apoptotic cell death pathway involving both caspases and mitochondria. The present work further explores the role of intracellular reduced glutathione (GSH) level in cell sensitivity to this cell death pathway. EXPERIMENTAL DESIGN Intracellular GSH level was measured by high-performance liquid chromatography. Cell death was detected by immunofluorescence after Hoechst 33342/propidium iodide staining. Reactive oxygen species production was evaluated by flow cytometry after dihydroethidium probe labeling. Western blot analysis was done to study stress-activated protein kinase/c-jun NH(2)-terminal kinase (SAPK/JNK) phosphorylation. The Student's t test was used to determine significance of the results. Three to six experiments were done. RESULTS GSH depletion enhanced apoptosis induced by TRAIL/cisplatin (CDDP) or TRAIL/5-fluorouracil (5-FU) combinations in both human HT29 colon carcinoma and HepG2 hepatocarcinoma cells, whereas it enhanced cytotoxicity induced only by TRAIL/CDDP in human primary hepatocytes. Our results further suggested that GSH depletion enhanced SAPK/JNK phosphorylation upon TRAIL/5-FU exposure and likely reduced the detoxification mechanisms of CDDP in HT29 cells. Resistance of Bcl-2-expressing HT29 and HepG2 cells to combined treatment was not overcome by GSH depletion, thus indicating that Bcl-2-mediated antiapoptotic effect occurs independently of intracellular GSH level. CONCLUSION GSH depletion could be useful to increase the therapeutic efficacy of cancer treatment by TRAIL/anticancer drug combinations. Furthermore, TRAIL/5-FU combination might be a potential anticancer treatment of human tumors, being ineffective on human primary hepatocytes and thus could be of interest in clinical cancer treatment. Nevertheless, Bcl-2 expression remains an important resistance factor.
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Affiliation(s)
- Olivier Meurette
- Institut National de la Santé et de la Recherche Médicale U620, Détoxication et Réparation Tissulaire, Faculté de Pharmacie, Université Rennes 1, Rennes, France
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14
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Abstract
Glutathione is an abundant natural tripeptide found within almost all cells. Glutathione is highly reactive and is often found conjugated to other molecules via its sulfhydryl moiety. It instils several vital roles within a cell including antioxidation, maintenance of the redox state, modulation of the immune response and detoxification of xenobiotics. With respect to cancer, glutathione metabolism is able to play both protective and pathogenic roles. It is crucial in the removal and detoxification of carcinogens, and alterations in this pathway, can have a profound effect on cell survival. However, by conferring resistance to a number of chemotherapeutic drugs, elevated levels of glutathione in tumour cells are able to protect such cells in bone marrow, breast, colon, larynx and lung cancers. Here we present a number of studies investigating the role of glutathione in promoting cancer, impeding chemotherapy, and the use of glutathione modulation to enhance anti-neoplastic therapy.
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Affiliation(s)
- Ganesaratnam K Balendiran
- Division of Immunology, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, CA 91010, USA.
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Rajasekaran NS, Sathyanarayanan S, Devaraj NS, Devaraj H. Chronic depletion of glutathione (GSH) and minimal modification of LDL in vivo: its prevention by glutathione mono ester (GME) therapy. Biochim Biophys Acta Mol Basis Dis 2004; 1741:103-12. [PMID: 15955453 DOI: 10.1016/j.bbadis.2004.11.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2004] [Revised: 11/12/2004] [Accepted: 11/16/2004] [Indexed: 11/17/2022]
Abstract
A decline in reduced glutathione (GSH) level is associated with aging and free radical mediated diseases. The objective of this study was to determine whether the chronic depletion of extra cellular GSH causes oxidative damage to the circulating macromolecules such as lipoproteins. Decreased concentrations of plasma glutathione, vitamin E and ascorbic acid were recorded in the rats treated with buthionine sulfoximine (BSO), a selective GSH inhibitor. In LDL isolated from BSO-treated animals, the concentration of malondialdehyde (MDA) and conjugated dienes were significantly increased (P<0.01), whereas the levels of vitamin E were decreased (P<0.01). The analysis of total and LDL cholesterol revealed significant changes between the control and experimental groups. Of interest, altered concentrations of lyso-phosphatidyl choline (Lyso-PC) and phosphatidyl choline (PC) were recorded from the BSO mediated minimally modified LDL. A negative correlation between LDL-BDC/MDA and its antioxidant capacity was noted. Upon in vitro oxidation with CuSO(4), the electrophoretic behavior of purified LDL-apoprotein-B on agarose gel showed an increased mobility in BSO-treated rats, indicative of in vivo modification of LDL to become susceptible for in vitro oxidation. The increased mobility of LDL (after in vitro oxidation) isolated from the BSO-treated animals correlates with a decrease in its amino groups, as determined by the trinitrobenzene sulfonic acid (TNBS) reactants. However, the mobility of LDL molecule was not altered due to BSO treatment in vivo. Interestingly, the minimal modification on LDL does not lead to any vascular damage in the dorsal aorta of the rats injected with BSO. The administration of glutathione monoester (GME), at a dose of 5 mmol/kg body weight, twice a day, for 30 days, to animals treated with l-buthionine-SR-sulfoximine (BSO, 4 mmol/kg body weight, twice a day, for 30 days) normalized the antioxidant status and prevented the minimal modifications on LDL. Thus, increasing the cellular GSH levels may trigger beneficial effects against oxidative stress.
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Dewhirst MW, Richardson R, Cardenas-Navia I, Cao Y. The relationship between the tumor physiologic microenvironment and angiogenesis. Hematol Oncol Clin North Am 2004; 18:973-90, vii. [PMID: 15474330 DOI: 10.1016/j.hoc.2004.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This article examines the pathophysiology of tumors, with an emphasis on how these features influence angiogenesis in tumors.
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Affiliation(s)
- Mark W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Room 201, Medical Science Research Building, Research Drive, Box 3455, Durham, NC 27710, USA.
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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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