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Leakey JEA, Seng JE, Barnas CR, Baker VM, Hart RW. A Mechanistic Basis for the Beneficial Effects of Caloric Restriction On Longevity and Disease: Consequences for the Interpretation of Rodent Toxicity Studies. Int J Toxicol 2016. [DOI: 10.1177/109158189801700203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Caloric restriction in rodents has been repeatedly shown to increase life span while reducing the severity and retarding the onset of both spontaneous and chemically induced neoplasms. These effects of caloric restriction are associated with a spectrum of biochemical and physiological changes that characterize the organism's adaptation to reduced caloric intake and provide the mechanistic basis for caloric restriction's effect on longevity. Here, we review evidence suggesting that the primary adaptation appears to be a rhythmic hypercorticism in the absence of elevated adrenocorticotropin (ACTH) levels. This characteristic hypercorticism evokes a spectrum of responses, including reduced body temperature and increased metabolic efficiency, decreased mitogenic response coupled with increased rates of apoptosis, reduced inflammatory response, reduced oxidative damage to proteins and DNA, reduced reproductive capacity, and altered drug-metabolizing enzyme expression. The net effect of these changes is to (1) decrease growth and metabolism in peripheral tissues to spare energy for central functions, and (2) increase the organism's capacity to withstand stress and chemical toxicity. Thus, caloric restriction research has uncovered an evolutionary mechanism that provides rodents with an adaptive advantage in conditions of fluctuating food supply. During periods of abundance, body growth and fecundity are favored over endurance and longevity. Conversely, during periods of famine, reproductive performance and growth are sacrificed to ensure survival of individuals to breed in better times. This phenomena can be observed in rodent populations that are used in toxicity testing. Improvements over the last 30 years in animal husbandry and nutrition, coupled with selective breeding for growth and fecundity, have resulted in several strains now exhibiting larger animals with reduced survival and increased incidence of background lesions. The mechanistic data from caloric restriction studies suggest that these large animals will also be more susceptible to chemically induced toxicity. This creates a problem in comparing tests performed on animals of different weights and comparing data generated today with the historical database. The rational use of caloric restriction to control body weight to within preset guidelines is a possible way of alleviating this problem.
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Affiliation(s)
- Julian E. A. Leakey
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - John E. Seng
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - Crissy R. Barnas
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA, Department of Clinical Pharmacology and Geriatrics,
Northwestern University, 303 E. Superior St., Chicago, IL 60611, USA
| | - Vanessa M. Baker
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - Ronald W. Hart
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
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Lauriola M, Enuka Y, Zeisel A, D'Uva G, Roth L, Sharon-Sevilla M, Lindzen M, Sharma K, Nevo N, Feldman M, Carvalho S, Cohen-Dvashi H, Kedmi M, Ben-Chetrit N, Chen A, Solmi R, Wiemann S, Schmitt F, Domany E, Yarden Y. Diurnal suppression of EGFR signalling by glucocorticoids and implications for tumour progression and treatment. Nat Commun 2014; 5:5073. [PMID: 25278152 PMCID: PMC4205848 DOI: 10.1038/ncomms6073] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 08/25/2014] [Indexed: 02/07/2023] Open
Abstract
Signal transduction by receptor tyrosine kinases (RTKs) and nuclear receptors for steroid hormones is essential for body homeostasis, but the cross-talk between these receptor families is poorly understood. We observed that glucocorticoids inhibit signalling downstream of EGFR, an RTK. The underlying mechanism entails suppression of EGFR's positive feedback loops and simultaneous triggering of negative feedback loops that normally restrain EGFR. Our studies in mice reveal that the regulation of EGFR's feedback loops by glucocorticoids translates to circadian control of EGFR signalling: EGFR signals are suppressed by high glucocorticoids during the active phase (night-time in rodents), while EGFR signals are enhanced during the resting phase. Consistent with this pattern, treatment of animals bearing EGFR-driven tumours with a specific kinase inhibitor was more effective if administered during the resting phase of the day, when glucocorticoids are low. These findings support a circadian clock-based paradigm in cancer therapy.
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Affiliation(s)
- Mattia Lauriola
- 1] Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel [2] Unit of Histology, Embryology and Applied Biology, Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, Bologna 40138, Italy
| | - Yehoshua Enuka
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Amit Zeisel
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gabriele D'Uva
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lee Roth
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Sharon-Sevilla
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Moshit Lindzen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Kirti Sharma
- Division of Molecular Genome Analysis, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany
| | - Nava Nevo
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Morris Feldman
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Silvia Carvalho
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hadas Cohen-Dvashi
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Merav Kedmi
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nir Ben-Chetrit
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alon Chen
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rossella Solmi
- Unit of Histology, Embryology and Applied Biology, Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, Bologna 40138, Italy
| | - Stefan Wiemann
- Division of Molecular Genome Analysis, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany
| | - Fernando Schmitt
- 1] Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8 [2] Department of Pathology, University Health Network, Toronto, Ontario, Canada M5G 2C4 [3] IPATIMUP, University of Porto, Porto 4200-465, Portugal
| | - Eytan Domany
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yosef Yarden
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
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Malcher-Lopes R, Buzzi M. Glucocorticoid-regulated crosstalk between arachidonic acid and endocannabinoid biochemical pathways coordinates cognitive-, neuroimmune-, and energy homeostasis-related adaptations to stress. VITAMINS AND HORMONES 2009; 81:263-313. [PMID: 19647116 DOI: 10.1016/s0083-6729(09)81011-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Arachidonic acid and its derivatives constitute the major group of signaling molecules involved in the innate immune response and its communication with all cellular and systemic aspects involved on homeostasis maintenance. Glucocorticoids spread throughout the organism their influences over key enzymatic steps of the arachidonic acid biochemical pathways, leading, in the central nervous system, to a shift favoring the synthesis of anti-inflammatory endocannabinoids over proinflammatory metabolites, such as prostaglandins. This shift modifies local immune-inflammatory response and neuronal activity to ultimately coordinate cognitive, behavioral, neuroendocrine, neuroimmune, physiological, and metabolic adjustments to basal and stress conditions. In the hypothalamus, a reciprocal feedback between glucocorticoids and arachidonate-containing molecules provides a mechanism for homeostatic control. This neurochemical switch is susceptible to fine-tuning by neuropeptides, cytokines, and hormones, such as leptin and interleukin-1beta, assuring functional integration between energy homeostasis control and the immune/stress response.
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Affiliation(s)
- Renato Malcher-Lopes
- Laboratory of Mass Spectrometry, EMBRAPA-Center for Genetic Resources and Biotechnology, Brasília-DF, Brazil
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Abstract
Tumor cell proliferation and metastasis proceed via a network of interdependent molecular events with a vast array of molecular players and signal transduction mechanisms differing in various types of human tumors. In the sequence of events necessary for carcinogenesis, arachidonate metabolites have been documented to play a significant role at several steps. Arachidonate metabolism in human cells occurs via several enzymatic pathways, including enzymes such as cyclo-oxygenases and lipoxygenases. This review pays particular attention to one member of the lipoxygenase family of enzymes, namely 12-lipoxygenase, since an arachidonate metabolite generated via 12-lipoxygenase action, 12(S)-HETE, has been shown to elicit various prometastatic effects of tumor cells in vivo and in vitro. We focus especially on mechanisms of activation and modulation of 12-lipoxygenase expression in human tumor cells, since various tumor cells express 12-lipoxygenase or are responsive to metabolites derived from 12-lipoxygenase action, thus offering a potential for successful therapeutic intervention against such tumors.
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Affiliation(s)
- Wolfgang Hagmann
- Deutsches Krebsforschungszentrum, Division of Tumor Biochemistry, Heidelberg, Germany
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Hagmann W, Borgers S. Requirement for epidermal growth factor receptor tyrosine kinase and for 12-lipoxygenase activity in the expression of 12-lipoxygenase in human epidermoid carcinoma cells. Biochem Pharmacol 1997; 53:937-42. [PMID: 9174106 DOI: 10.1016/s0006-2952(96)00833-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We studied the dependency of basal 12-lipoxygenase (12-LOX; arachidonate:oxygen 12-oxidoreductase, EC 1.13.11.31) expression and activity on functional protein tyrosine kinase of the epidermal growth factor receptor (EGF-R) and on 12-LOX activity in human A431 epidermoid carcinoma cells. Treatment of cells with inhibitors of high specificity for EGF-R tyrosine kinase, namely PD 153035 and 4,5-dianilinophthalimide (DAPH1), decreased cellular 12-LOX at mRNA, protein, and activity levels in a time- and dose-dependent manner, with PD 153035 being effective at concentrations below 1 microM. After 24-hr incubation with 10 microM PD 153035 or DAPH1, 12-LOX activity dropped to 14% (39%), and 12-LOX protein to 25% (24%) of control level. Inhibition of 12-LOX activity by the compound N-benzyl-N-hydroxy-5-phenylpentanamide (BHPP) also resulted in a substantial decrease in 12-LOX protein expression. 12-LOX mRNA levels were diminished or undetectable by reverse transcription-polymerase chain reaction after cell treatment with these inhibitors. Our results suggest that basal 12-LOX expression in A431 tumor cells largely depends on functional EGF-R tyrosine kinase, and that 12-LOX activity is required in the EGF-elicited intracellular signaling maintaining the expression of 12-LOX.
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Affiliation(s)
- W Hagmann
- Division of Tumor Biochemistry, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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