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Brix KV, Baken S, Poland CA, Blust R, Pope LJ, Tyler CR. Challenges and Recommendations in Assessing Potential Endocrine-Disrupting Properties of Metals in Aquatic Organisms. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:2564-2579. [PMID: 37671843 DOI: 10.1002/etc.5741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 09/07/2023]
Abstract
New tools and refined frameworks for identifying and regulating endocrine-disrupting chemicals (EDCs) are being developed as our scientific understanding of how they work advances. Although focus has largely been on organic chemicals, the potential for metals to act as EDCs in aquatic systems is receiving increasing attention. Metal interactions with the endocrine system are complicated because some metals are essential to physiological systems, including the endocrine system, and nonessential metals can have similar physiochemical attributes that allow substitution into or interference with these systems. Consequently, elevated metal exposure could potentially cause endocrine disruption (ED) but can also cause indirect effects on the endocrine system via multiple pathways or elicit physiologically appropriate compensatory endocrine-mediated responses (endocrine modulation). These latter two effects can be confused with, but are clearly not, ED. In the present study, we provide several case studies that exemplify the challenges encountered in evaluating the endocrine-disrupting (ED) potential of metals, followed by recommendations on how to meet them. Given that metals have multiple modes of action (MOAs), we recommend that assessments use metal-specific adverse outcome pathway networks to ensure that accurate causal links are made between MOAs and effects on the endocrine system. We recommend more focus on establishing molecular initiating events for chronic metal toxicity because these are poorly understood and would reduce uncertainty regarding the potential for metals to be EDCs. Finally, more generalized MOAs such as oxidative stress could be involved in metal interactions with the endocrine system, and we suggest it may be experimentally efficient to evaluate these MOAs when ED is inferred. These experiments, however, must provide explicit linkage to the ED endpoints of interest. Environ Toxicol Chem 2023;42:2564-2579. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Kevin V Brix
- EcoTox, Miami, Florida, USA
- Rosenstiel School of Marine, Atmospheric & Earth Science, University of Miami, Miami, Florida, USA
| | - Stijn Baken
- International Copper Association, Brussels, Belgium
| | - Craig A Poland
- Regulatory Compliance Limited, Loanhead, United Kingdom
- Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Ronny Blust
- Department of Biology, University of Antwerp, Antwerp, Belgium
| | | | - Charles R Tyler
- Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
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Abstract
Gastric acid secretion (i) facilitates digestion of protein as well as absorption of micronutrients and certain medications, (ii) kills ingested microorganisms, including Helicobacter pylori, and (iii) prevents bacterial overgrowth and enteric infection. The principal regulators of acid secretion are the gastric peptides gastrin and somatostatin. Gastrin, the major hormonal stimulant for acid secretion, is synthesized in pyloric mucosal G cells as a 101-amino acid precursor (preprogastrin) that is processed to yield biologically active amidated gastrin-17 and gastrin-34. The C-terminal active site of gastrin (Trp-Met-Asp-Phe-NH2 ) binds to gastrin/CCK2 receptors on parietal and, more importantly, histamine-containing enterochromaffin-like (ECL) cells, located in oxyntic mucosa, to induce acid secretion. Histamine diffuses to the neighboring parietal cells where it binds to histamine H2 -receptors coupled to hydrochloric acid secretion. Gastrin is also a trophic hormone that maintains the integrity of gastric mucosa, induces proliferation of parietal and ECL cells, and is thought to play a role in carcinogenesis. Somatostatin, present in D cells of the gastric pyloric and oxyntic mucosa, is the main inhibitor of acid secretion, particularly during the interdigestive period. Somatostatin exerts a tonic paracrine restraint on gastrin secretion from G cells, histamine secretion from ECL cells, and acid secretion from parietal cells. Removal of this restraint, for example by activation of cholinergic neurons during ingestion of food, initiates and maximizes acid secretion. Knowledge regarding the structure and function of gastrin, somatostatin, and their respective receptors is providing novel avenues to better diagnose and manage acid-peptic disorders and certain cancers. Published 2020. Compr Physiol 10:197-228, 2020.
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Affiliation(s)
- Mitchell L Schubert
- Division of Gastroenterology, Department of Medicine, Virginia Commonwealth University Health System, Richmond, Virginia, USA.,Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Ischia J, Bolton DM, Patel O. Why is it worth testing the ability of zinc to protect against ischaemia reperfusion injury for human application. Metallomics 2019; 11:1330-1343. [PMID: 31204765 DOI: 10.1039/c9mt00079h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ischaemia (interruption in the blood/oxygen supply) and subsequent damage induced by reperfusion (restoration of blood/oxygen supply) ultimately leads to cell death, tissue injury and permanent organ dysfunction. The impact of ischaemia reperfusion injury (IRI) is not limited to heart attack and stroke but can be extended to patients undergoing surgeries such as partial nephrectomy for renal cancer, liver resection for colorectal cancer liver metastasis, cardiopulmonary bypass, and organ transplantation. Unfortunately, there are no drugs that can protect organs against the inevitable peril of IRI. Recent data show that a protocol incorporating specific Zn formulation, dosage, number of dosages, time of injection, and mode of Zn delivery (intravenous) and testing of efficacy in a large preclinical sheep model of IRI strongly supports human trials of Zn preconditioning. No doubt, scepticism still exists among funding bodies and research fraternity on whether Zn, a naturally occurring metal, will work where everything else has failed. Therefore, in this article, we review the conflicting evidence on the promoter and protector role of Zn in the case of IRI and highlight factors that may help explain the contradictory evidence. Finally, we review the literature related to the knowledge of Zn's mechanism of action on ROS generation, apoptosis, HIF activation, inflammation, and signal transduction pathways, which highlight Zn's likelihood of success compared to various other interventions targeting IRI.
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Affiliation(s)
- Joseph Ischia
- Department of Surgery, The University of Melbourne, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia. and Department of Urology, Austin Health, Heidelberg, Victoria, Australia
| | - Damien M Bolton
- Department of Surgery, The University of Melbourne, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia. and Department of Urology, Austin Health, Heidelberg, Victoria, Australia
| | - Oneel Patel
- Department of Surgery, The University of Melbourne, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia.
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Stevenson MJ, Uyeda KS, Harder NHO, Heffern MC. Metal-dependent hormone function: the emerging interdisciplinary field of metalloendocrinology. Metallomics 2019; 11:85-110. [PMID: 30270362 PMCID: PMC10249669 DOI: 10.1039/c8mt00221e] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
For over 100 years, there has been an incredible amount of knowledge amassed concerning hormones in the endocrine system and their central role in human health. Hormones represent a diverse group of biomolecules that are released by glands, communicate signals to their target tissue, and are regulated by feedback loops to maintain organism health. Many disease states, such as diabetes and reproductive disorders, stem from misregulation or dysfunction of hormones. Increasing research is illuminating the intricate roles of metal ions in the endocrine system where they may act advantageously in concert with hormones or deleteriously catalyze hormone-associated disease states. As the critical role of metal ions in the endocrine system becomes more apparent, it is increasingly important to untangle the complex mechanisms underlying the connections between inorganic biochemistry and hormone function to understand and control endocrinological phenomena. This tutorial review harmonizes the interdisciplinary fields of endocrinology and inorganic chemistry in the newly-termed field of "metalloendocrinology". We describe examples linking metals to both normal and aberrant hormone function with a focus on highlighting insight to molecular mechanisms. Hormone activities related to both essential metal micronutrients, such as copper, iron, zinc, and calcium, and disruptive nonessential metals, such as lead and cadmium are discussed.
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Affiliation(s)
- Michael J Stevenson
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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O'Kane D, Gibson L, May CN, du Plessis J, Shulkes A, Baldwin GS, Bolton D, Ischia J, Patel O. Zinc preconditioning protects against renal ischaemia reperfusion injury in a preclinical sheep large animal model. Biometals 2018; 31:821-834. [PMID: 29974287 DOI: 10.1007/s10534-018-0125-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 01/11/2023]
Abstract
Ischaemia-reperfusion injury (IRI) during various surgical procedures, including partial nephrectomy for kidney cancer or renal transplantation, is a major cause of acute kidney injury and chronic kidney disease. Currently there are no drugs or methods for protecting human organs, including the kidneys, against the peril of IRI. The aim of this study was therefore to investigate the reno-protective effect of Zn2+ preconditioning in a clinically relevant large animal sheep model of IRI. Further the reno-protective effectiveness of Zn2+ preconditioning was tested on normal human kidney cell lines HK-2 and HEK293. Anaesthetised sheep were subjected to uninephrectomy and 60 min of renal ischaemia followed by reperfusion. Sheep were preconditioned with intravenous injection of zinc chloride prior to occlusion. Serum creatinine and urea were measured before ischaemia and for 7 days after reperfusion. HK-2 and HEK293 cells were subjected to in vitro IRI using the oxygen- and glucose-deprivation model. Zn2+ preconditioning reduced ischaemic burden determined by creatinine and urea rise over time by ~ 70% in sheep. Zn2+ preconditioning also increased the survival of normal human kidney cells subjected to cellular stress such as hypoxia, hydrogen peroxide injury, and serum starvation. Overall, our protocol incorporating specific Zn2+ dosage, number of dosages (two), time of injection (24 and 4 h prior), mode of Zn2+ delivery (IV) and testing of efficacy in a rat model, a large preclinical sheep model of IRI and cells of human origin has laid the foundation for assessment of the benefit of Zn2+ preconditioning for human applications.
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Affiliation(s)
- Dermot O'Kane
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
- Department of Urology, Austin Health, Heidelberg, VIC, Australia
| | - Luke Gibson
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
- Department of Urology, Austin Health, Heidelberg, VIC, Australia
| | - Clive N May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Justin du Plessis
- Australian Clinical Laboratories, Austin Health, Heidelberg, VIC, Australia
| | - Arthur Shulkes
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
| | - Graham S Baldwin
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
| | - Damien Bolton
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
- Department of Urology, Austin Health, Heidelberg, VIC, Australia
| | - Joseph Ischia
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia
- Department of Urology, Austin Health, Heidelberg, VIC, Australia
| | - Oneel Patel
- The University of Melbourne Department of Surgery, Austin Health, Studley Rd., Heidelberg, VIC, 3084, Australia.
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Kowalski-Chauvel A, Teissier G, Toulas C, Cohen-Jonathan-Moyal E, Seva C. By modulating α2β1 integrin signalling, gastrin increases adhesion oF AGS-GR gastric cancer cells. Exp Cell Res 2018; 362:498-503. [PMID: 29253536 DOI: 10.1016/j.yexcr.2017.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 01/01/2023]
Abstract
Peritoneal metastasis is a major cause of recurrence of gastric cancer and integrins are key molecules involved in gastric cancer cells attachment to the peritoneum. The peptide hormone, gastrin, initially identified for its role in gastric acid secretion is also a growth factor for gastric mucosa. Gastrin has also been shown to contribute to gastric cancers progression. Here, we provide the first evidence that gastrin increases the adhesion of gastric cancer cells. Gastrin treatment induces the expression of α2 integrin subunit through a mechanism that involves the ERK pathway. We also observed in response to gastrin an increase in the amount of α2 integrin associated with β1subunit. In addition, gastrin-stimulated cell adhesion was blocked with an anti-α2β1 integrin neutralizing antibody. We also show that gastrin activates the integrin pathway via the phosphorylation of β1 integrin by a Src family kinase. This mechanism may contribute to the enhancement of cell adhesion observed in response to gastrin since we found an inhibition of gastrin-mediated cell adhesion when cells were treated with a Src inhibitor. By regulating one of the key step of the metastatic process gastrin might contribute to increase the aggressive behaviour of human gastric tumours.
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Affiliation(s)
- Aline Kowalski-Chauvel
- INSERM UMR.1037-Cancer Research Center of Toulouse (CRCT)/University Paul Sabatier Toulouse III, team 11, Oncopole 2 Avenue Hubert Curien, CS 53717, 31037 Toulouse, France
| | - Guy Teissier
- INSERM UMR.1037-Cancer Research Center of Toulouse (CRCT)/University Paul Sabatier Toulouse III, team 11, Oncopole 2 Avenue Hubert Curien, CS 53717, 31037 Toulouse, France
| | - Christine Toulas
- INSERM UMR.1037-Cancer Research Center of Toulouse (CRCT)/University Paul Sabatier Toulouse III, team 11, Oncopole 2 Avenue Hubert Curien, CS 53717, 31037 Toulouse, France; IUCT-oncopole Toulouse, France
| | - Elizabeth Cohen-Jonathan-Moyal
- INSERM UMR.1037-Cancer Research Center of Toulouse (CRCT)/University Paul Sabatier Toulouse III, team 11, Oncopole 2 Avenue Hubert Curien, CS 53717, 31037 Toulouse, France; IUCT-oncopole Toulouse, France
| | - Catherine Seva
- INSERM UMR.1037-Cancer Research Center of Toulouse (CRCT)/University Paul Sabatier Toulouse III, team 11, Oncopole 2 Avenue Hubert Curien, CS 53717, 31037 Toulouse, France.
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Pan S, An L, Meng X, Li L, Ren F, Guan Y. MgCl 2 and ZnCl 2 promote human umbilical vein endothelial cell migration and invasion and stimulate epithelial-mesenchymal transition via the Wnt/β-catenin pathway. Exp Ther Med 2017; 14:4663-4670. [PMID: 29201165 PMCID: PMC5704337 DOI: 10.3892/etm.2017.5144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 02/24/2017] [Indexed: 02/06/2023] Open
Abstract
Previous studies have demonstrated that magnesium and zinc ions promote the migration and epithelial-mesenchymal transition (EMT) of cancer/endothelial cells. However, the impact of MgCl2 and ZnCl2 on the migration, invasion and EMT of human umbilical vein endothelial cells (HUVECs) and the involved mechanisms remain unclear. In the present study, HUVECs were incubated with various doses of MgCl2 and ZnCl2. The optimum concentrations of MgCl2 and ZnCl2 were selected by MTT assay. The migration and invasion capabilities of HUVECs were analyzed by Transwell assays. Subsequently, the expression of matrix metalloproteinase (MMP)-2 and MMP-9 mRNA and protein were determined by reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA. MMP-2 and MMP-9 activities were measured by gelatin zymography. Immunofluorescence staining was performed to investigate cytoskeletal dynamics using Acti-stain™ 488 Fluorescent Phalloidin. Subsequently, the expression of EMT-related markers at the mRNA and protein levels and the activation of Wnt/β-catenin signaling were analyzed. The results identified increases in MMP-2 and MMP-9 expression and activity, indicating that MgCl2 and ZnCl2 promoted HUVEC migration and invasion. In addition, MgCl2 and ZnCl2 treatment induced cytoskeleton remodeling and stimulated EMT via activation of the Wnt/β-catenin signaling pathway, characterized by a decrease in E-cadherin and increases in N-cadherin, vimentin and Snail. These results suggest that MgCl2 and ZnCl2 may enhance the migration and invasion capabilities of HUVECs and promote EMT through the Wnt/β-catenin pathway.
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Affiliation(s)
- Shuang Pan
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Liwen An
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xin Meng
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Liming Li
- College of Life and Health Sciences, Northeastern University, Shenyang, Liaoning 110819, P.R. China
| | - Fu Ren
- Department of Anatomy, Liaoning Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Yifu Guan
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, P.R. China
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Rao K, Sethi K, Ischia J, Gibson L, Galea L, Xiao L, Yim M, Chang M, Papa N, Bolton D, Shulkes A, Baldwin GS, Patel O. Protective effect of zinc preconditioning against renal ischemia reperfusion injury is dose dependent. PLoS One 2017; 12:e0180028. [PMID: 28686686 PMCID: PMC5501469 DOI: 10.1371/journal.pone.0180028] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 06/08/2017] [Indexed: 11/25/2022] Open
Abstract
Objectives Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury and chronic kidney disease. Two promising preconditioning methods for the kidney, intermittent arterial clamping (IC) and treatment with the hypoxia mimetic cobalt chloride, have never been directly compared. Furthermore, the protective efficacy of the chemically related transition metal Zn2+ against renal IRI is unclear. Although Co2+ ions have been shown to protect the kidney via hypoxia inducible factor (HIF), the effect of Zn2+ ions on the induction of HIF1α, HIF2α and HIF3α has not been investigated previously. Materials and methods The efficacy of different preconditioning techniques was assessed using a Sprague-Dawley rat model of renal IRI. Induction of HIF proteins following Zn2+ treatment of the human kidney cell lines HK-2 (immortalized normal tubular cells) and ACHN (renal cancer) was measured using Western Blot. Results Following 40 minutes of renal ischemia in rats, cobalt preconditioning offered greater protection against renal IRI than IC as evidenced by lower peak serum creatinine and urea concentrations. ZnCl2 (10 mg/kg) significantly lowered the creatinine and urea concentrations compared to saline-treated control rats following a clinically relevant 60 minutes of ischemia. Zn2+ induced expression of HIF1α and HIF2α but not HIF3α in HK-2 and ACHN cells. Conclusion ZnCl2 preconditioning protects against renal IRI in a dose-dependent manner. Further studies are warranted to determine the possible mechanisms involved, and to assess the benefit of ZnCl2 preconditioning for clinical applications.
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Affiliation(s)
- Kenny Rao
- Department of Surgery, The University of Melbourne Victoria, Australia
- Department of Urology Austin Health, Victoria, Australia
| | - Kapil Sethi
- Department of Surgery, The University of Melbourne Victoria, Australia
- Department of Urology Austin Health, Victoria, Australia
| | - Joseph Ischia
- Department of Surgery, The University of Melbourne Victoria, Australia
- Department of Urology Austin Health, Victoria, Australia
| | - Luke Gibson
- Department of Surgery, The University of Melbourne Victoria, Australia
- Department of Urology Austin Health, Victoria, Australia
| | - Laurence Galea
- Department of Anatomical Pathology, Austin Health, Victoria, Australia
| | - Lin Xiao
- Department of Surgery, The University of Melbourne Victoria, Australia
| | - Mildred Yim
- Department of Surgery, The University of Melbourne Victoria, Australia
| | - Mike Chang
- Department of Surgery, The University of Melbourne Victoria, Australia
| | - Nathan Papa
- Department of Urology Austin Health, Victoria, Australia
| | - Damien Bolton
- Department of Surgery, The University of Melbourne Victoria, Australia
- Department of Urology Austin Health, Victoria, Australia
| | - Arthur Shulkes
- Department of Surgery, The University of Melbourne Victoria, Australia
| | - Graham S. Baldwin
- Department of Surgery, The University of Melbourne Victoria, Australia
| | - Oneel Patel
- Department of Surgery, The University of Melbourne Victoria, Australia
- * E-mail:
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Marshall KM, Laval M, Estacio O, Hudson DF, Kalitsis P, Shulkes A, Baldwin GS, Patel O. Activation by zinc of the human gastrin gene promoter in colon cancer cells in vitro and in vivo. Metallomics 2015; 7:1390-8. [PMID: 26404630 DOI: 10.1039/c5mt00147a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over-expression of growth factors can contribute to the development and progression of cancer, and gastrins in particular have been implicated in accelerating the development of gastrointestinal cancers. Previously our group showed that hypoxia, cobalt chloride (a hypoxia mimetic) and zinc chloride could activate the expression of the gastrin gene in vitro. To characterise activation of the gastrin promoter by zinc ions further in vivo, TALEN technology was used to engineer a luciferase reporter construct into the endogenous human gastrin gene promoter in SW480 colon cancer cells. Gastrin promoter activity in the resultant Gast(luc) SW480 colon cancer cells was then measured by bioluminescence in cell culture and in tumour xenografts in SCID mice. Activation of intracellular signalling pathways was assessed by Western blotting. Activation of the gastrin promoter by zinc ions was concentration dependent in vitro and in vivo. Zinc ions significantly stimulated phosphorylation of ERK1/2 (MAPK pathway) but not of Akt (PI3K pathway). We conclude that the endogenous gastrin promoter is responsive to zinc ions, likely via activation of the MAPK pathway.
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Affiliation(s)
- Kathryn M Marshall
- The Department of Surgery, University of Melbourne, Austin Health, Studley Rd, Heidelberg, Victoria 3084, Australia.
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McCormick NH, King J, Krebs N, Soybel DI, Kelleher SL. Redistribution of tissue zinc pools during lactation and dyshomeostasis during marginal zinc deficiency in mice. J Trace Elem Med Biol 2015; 29:170-5. [PMID: 24974135 PMCID: PMC4258524 DOI: 10.1016/j.jtemb.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 11/28/2022]
Abstract
Zinc (Zn) requirements are increased during lactation. Increased demand is partially met through increased Zn absorption from the diet. It is estimated that 60-80% of women of reproductive age are at risk for Zn deficiency due to low intake of bioavailable Zn and increased demands during pregnancy and lactation. How Zn is redistributed within the body to meet the demands of lactation, and how Zn deficiency affects this process, is not understood. Female C57bl/6J mice were fed a control (ZA; 30mg Zn/kg) or a marginally Zn deficient (ZD; 15mg Zn/kg) diet for 30 days prior to mating through mid-lactation and compared with nulliparous mice fed the same diets. While stomach and plasma Zn concentration increased during lactation in mice fed ZA, mice fed ZD had lower stomach Zn concentration and abrogated plasma Zn levels during lactation. Additionally, femur Zn decreased during lactation in mice fed ZA, while mice fed ZD did not experience this decrease. Furthermore, red blood cell, pancreas, muscle and mammary gland Zn concentration increased, and liver and adrenal gland Zn decreased during lactation, independent of diet, while kidney Zn concentration increased only in mice fed ZD. Finally, maternal Zn deficiency significantly increased the liver Zn concentration in offspring but decreased weight gain and survival. This study provides novel insight into how Zn is redistributed to meet the increased metabolic demands of lactation and how marginal Zn deficiency interferes with these homeostatic adjustments.
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Affiliation(s)
- Nicholas H McCormick
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Janet King
- Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Nancy Krebs
- University of Colorado, School of Medicine, Aurora, CO 80045, USA
| | - David I Soybel
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA; Departments of Surgery and Cell and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA 17033, USA
| | - Shannon L Kelleher
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA; Departments of Surgery and Cell and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA 17033, USA.
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Abstract
PURPOSE OF REVIEW This review summarizes the past year's literature regarding the neural, paracrine, hormonal, and intracellular regulation of gastric acid secretion. RECENT FINDINGS Gastric acid facilitates the digestion of protein as well as the absorption of iron, calcium, vitamin B12, and certain medications. High gastric acidity, in combination with pepsin and lipase, kills ingested microorganisms and may play a role in preventing bacterial overgrowth, enteric infection, and possibly spontaneous bacterial peritonitis, community-acquired pneumonia, and infection with Mycobacterium tuberculosis. Stimulants of acid secretion include histamine, gastrin, acetylcholine, and ghrelin. Inhibitors include somatostatin, gastric inhibitory polypeptide, calcitonin gene-related peptide, and adrenomedullin. Helicobacter pylori stimulates or inhibits depending upon the time course of infection and the area of the stomach predominantly infected. Proteins implicated in H-K-ATPase membrane trafficking include myosin IIB, F-actin, ezrin, and Rab GTPases. SUMMARY Our understanding of the regulation of gastric acid secretion continues to advance. Such knowledge is crucial for the management of acid-peptic disorders and the development of novel medications, such as cholecystokinin-2 receptor antagonists.
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