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Loh D, Reiter RJ. Melatonin: Regulation of Prion Protein Phase Separation in Cancer Multidrug Resistance. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030705. [PMID: 35163973 PMCID: PMC8839844 DOI: 10.3390/molecules27030705] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 12/13/2022]
Abstract
The unique ability to adapt and thrive in inhospitable, stressful tumor microenvironments (TME) also renders cancer cells resistant to traditional chemotherapeutic treatments and/or novel pharmaceuticals. Cancer cells exhibit extensive metabolic alterations involving hypoxia, accelerated glycolysis, oxidative stress, and increased extracellular ATP that may activate ancient, conserved prion adaptive response strategies that exacerbate multidrug resistance (MDR) by exploiting cellular stress to increase cancer metastatic potential and stemness, balance proliferation and differentiation, and amplify resistance to apoptosis. The regulation of prions in MDR is further complicated by important, putative physiological functions of ligand-binding and signal transduction. Melatonin is capable of both enhancing physiological functions and inhibiting oncogenic properties of prion proteins. Through regulation of phase separation of the prion N-terminal domain which targets and interacts with lipid rafts, melatonin may prevent conformational changes that can result in aggregation and/or conversion to pathological, infectious isoforms. As a cancer therapy adjuvant, melatonin could modulate TME oxidative stress levels and hypoxia, reverse pH gradient changes, reduce lipid peroxidation, and protect lipid raft compositions to suppress prion-mediated, non-Mendelian, heritable, but often reversible epigenetic adaptations that facilitate cancer heterogeneity, stemness, metastasis, and drug resistance. This review examines some of the mechanisms that may balance physiological and pathological effects of prions and prion-like proteins achieved through the synergistic use of melatonin to ameliorate MDR, which remains a challenge in cancer treatment.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
- Correspondence: (D.L.); (R.J.R.)
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health San Antonio, San Antonio, TX 78229, USA
- Correspondence: (D.L.); (R.J.R.)
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Premabati Y, Singh KM, Gupta BBP. Opposite effects of photoperiod and temperature on circadian rhythms of pineal arylalkylamine N-acetyltransferas (AANAT) activity and circulating levels of thyroid hormones in airbreathing catfish, Clarias gariepinus. BIOL RHYTHM RES 2020. [DOI: 10.1080/09291016.2020.1734370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Yumkhaibam Premabati
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
| | - Kshetrimayum Manisana Singh
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
| | - Braj Bansh Prasad Gupta
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
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Espino J, Rodríguez AB, Pariente JA. Melatonin and Oxidative Stress in the Diabetic State: Clinical Implications and Potential Therapeutic Applications. Curr Med Chem 2019; 26:4178-4190. [PMID: 29637854 DOI: 10.2174/0929867325666180410094149] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 02/07/2023]
Abstract
All living organisms exhibit circadian rhythms, which govern the majority of biological functions, including metabolic processes. Misalignment of these circadian rhythms increases the risk of developing metabolic diseases. Thus, disruption of the circadian system has been proven to affect the onset of type 2 diabetes mellitus (T2DM). In this context, the pineal indoleamine melatonin is a signaling molecule able to entrain circadian rhythms. There is mounting evidence that suggests a link between disturbances in melatonin production and impaired insulin, glucose, lipid metabolism, and antioxidant capacity. Besides, several genetic association studies have causally associated various single nucleotide polymorphysms (SNPs) of the human MT2 receptor with increased risk of developing T2DM. Taken together, these data suggest that endogenous as well as exogenous melatonin may influence diabetes and associated metabolic disturbances not only by regulating insulin secretion but also by providing protection against reactive oxygen species (ROS) since pancreatic β-cells are very susceptible to oxidative stress due to their low antioxidant capacity.
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Affiliation(s)
- Javier Espino
- Department of Physiology (Neuroimmunophysiology and Chrononutrition Research Group), Faculty of Science, University of Extremadura, Badajoz, Spain
| | - Ana B Rodríguez
- Department of Physiology (Neuroimmunophysiology and Chrononutrition Research Group), Faculty of Science, University of Extremadura, Badajoz, Spain
| | - José A Pariente
- Department of Physiology (Neuroimmunophysiology and Chrononutrition Research Group), Faculty of Science, University of Extremadura, Badajoz, Spain
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Tan DX, Manchester LC, Esteban-Zubero E, Zhou Z, Reiter RJ. Melatonin as a Potent and Inducible Endogenous Antioxidant: Synthesis and Metabolism. Molecules 2015; 20:18886-906. [PMID: 26501252 PMCID: PMC6332205 DOI: 10.3390/molecules201018886] [Citation(s) in RCA: 386] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 11/17/2022] Open
Abstract
Melatonin is a tryptophan-derived molecule with pleiotropic activities. It is present in almost all or all organisms. Its synthetic pathway depends on the species in which it is measured. For example, the tryptophan to melatonin pathway differs in plants and animals. It is speculated that the melatonin synthetic machinery in eukaryotes was inherited from bacteria as a result of endosymbiosis. However, melatonin's synthetic mechanisms in microorganisms are currently unknown. Melatonin metabolism is highly complex with these enzymatic processes having evolved from cytochrome C. In addition to its enzymatic degradation, melatonin is metabolized via pseudoenzymatic and free radical interactive processes. The metabolic products of these processes overlap and it is often difficult to determine which process is dominant. However, under oxidative stress, the free radical interactive pathway may be featured over the others. Because of the complexity of the melatonin degradative processes, it is expected that additional novel melatonin metabolites will be identified in future investigations. The original and primary function of melatonin in early life forms such as in unicellular organisms was as a free radical scavenger and antioxidant. During evolution, melatonin was selected as a signaling molecule to transduce the environmental photoperiodic information into an endocrine message in multicellular organisms and for other purposes as well. As an antioxidant, melatonin exhibits several unique features which differ from the classic antioxidants. These include its cascade reaction with free radicals and its capacity to be induced under moderate oxidative stress. These features make melatonin a potent endogenously-occurring antioxidant that protects organisms from catastrophic oxidative stress.
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Affiliation(s)
- Dun-Xian Tan
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Lucien C Manchester
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Eduardo Esteban-Zubero
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Zhou Zhou
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Russel J Reiter
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
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Tan DX, Manchester LC, Fuentes-Broto L, Paredes SD, Reiter RJ. Significance and application of melatonin in the regulation of brown adipose tissue metabolism: relation to human obesity. Obes Rev 2011; 12:167-88. [PMID: 20557470 DOI: 10.1111/j.1467-789x.2010.00756.x] [Citation(s) in RCA: 222] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A worldwide increase in the incidence of obesity indicates the unsuccessful battle against this disorder. Obesity and the associated health problems urgently require effective strategies of treatment. The new discovery that a substantial amount of functional brown adipose tissue (BAT) is retained in adult humans provides a potential target for treatment of human obesity. BAT is active metabolically and disposes of extra energy via generation of heat through uncoupling oxidative phosphorylation in mitochondria. The physiology of BAT is readily regulated by melatonin, which not only increases recruitment of brown adipocytes but also elevates their metabolic activity in mammals. It is speculated that the hypertrophic effect and functional activation of BAT induced by melatonin may likely apply to the human. Thus, melatonin, a naturally occurring substance with no reported toxicity, may serve as a novel approach for treatment of obesity. Conversely, because of the availability of artificial light sources, excessive light exposure after darkness onset in modern societies should be considered a potential contributory factor to human obesity as light at night dramatically reduces endogenous melatonin production. In the current article, the potential associations of melatonin, BAT, obesity and the medical implications are discussed.
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Affiliation(s)
- D-X Tan
- Department of Cellular and Structural Biology, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Haldar C, Sharma S, Singh SS. Reproductive phase dependent circadian variations of plasma melatonin, testosterone, thyroxine and corticosterone in Indian palm squirrel,Funambulus pennanti. BIOL RHYTHM RES 2006. [DOI: 10.1080/09291010500224215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sato T, Tachiwana T, Takata K, Tay TW, Ishii M, Nakamura R, Kimura S, Kanai Y, Kurohmaru M, Hayashi Y. Testicular dynamics in Syrian hamsters exposed to both short photoperiod and low ambient temperature. Anat Histol Embryol 2005; 34:220-4. [PMID: 15996122 DOI: 10.1111/j.1439-0264.2005.00599.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The object of this study was to determine the details of morphological dynamics of spermatogenesis in Syrian hamsters exposed to both short photoperiod and low ambient temperature. Eight-week-old male hamsters, kept in a long photoperiod (14 h L, 10 h D), were transferred to a short photoperiod (6 h L, 18 h D) and kept there for 13 weeks to induce testicular regression. Some hamsters were then transferred from the room at 23 degrees C to that at 5 degrees C (5 degrees C group). Remaining hamsters were continuously kept at 23 degrees C (23 degrees C group). Thereafter, the morphology was examined. As a result, it took only 8 weeks until spermatogenesis recovered in the 23 degrees C group. However, it was not until 20 weeks that spermatogenesis was recognized in the 5 degrees C group. As the regulation of seasonal testicular activity is characterized by coordinated shifts in the relationships among mitosis, meiosis, and apoptosis, the changes in the proliferative and apoptotic activities were examined. Although no significant difference in proliferative activity of spermatogonia between the 5 degrees C and the 23 degrees C groups was confirmed, a notable increase in the rate of apoptosis was observed in the 5 degrees C group. Furthermore, this increase was more salient during the hibernation period. These findings suggest that both cold ambient temperature and hibernation caused the delay of testicular recrudescence and this delay arose from the increase of apoptotic activity but not the change in proliferative activity in spermatogonia in the 5 degrees C group.
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Affiliation(s)
- T Sato
- Department of Veterinary Anatomy, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Larkin JE, Jones J, Zucker I. Temperature dependence of gonadal regression in Syrian hamsters exposed to short day lengths. Am J Physiol Regul Integr Comp Physiol 2002; 282:R744-52. [PMID: 11832395 DOI: 10.1152/ajpregu.00299.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to determine whether ambient temperature (T(a)) affects gonadal function by altering the rate at which circadian rhythms entrain to short day lengths. Syrian hamsters were housed in cages where they received 14 h of light per day ("long days," 14L) at 22 degrees C. Hamsters were then transferred to cages to receive 10 h of light per day ("short days," 10L) and kept at 5, 22, or 28 degrees C or were maintained in 14L at 22 degrees C. Body mass and estimated testis volume as well as duration of nocturnal locomotor activity (alpha), previously established as a reliable indicator of the duration of nocturnal melatonin secretion, were determined over the course of 24 wk. Testicular regression in short days was accelerated by 4 wk at 5 degrees C and delayed by 3 wk at 28 degrees C relative to 22 degrees C. The interval between alpha-expansion and initiation of testicular regression was markedly affected by T(a) with delays of 0, 3, and 6 wk at 5, 22, and 28 degrees C, respectively. All hamsters held at 5 and 22 degrees C underwent testicular regression, but 25% of those maintained at 28 degrees C failed to do so. We suggest that T(a) modulates testicular regression primarily by affecting responsiveness of neuroendocrine target tissues to long melatonin signals.
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Affiliation(s)
- Jennie E Larkin
- Department of Psychology, University of California, Berkeley, California 94270-1650, USA.
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Haldar C, Alipreeta. Reproductive Phase Dependent Photosensitivity of Gonad and Pineal Gland of a Short-Nosed Fruit Bat, Cynopterus sphinx. Zoolog Sci 2001. [DOI: 10.2108/zsj.18.843] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
The role exerted by melatonin in human physiology has not been completely ascertained. Melatonin levels have been measured in different physiopathological conditions, but the effects induced by melatonin administration or withdrawal have been tested only recently. Some effects have been clearly documented. Melatonin has hypothermic properties, and its nocturnal secretion generates about 40% of the amplitude of the circadian body temperature rhythm. Melatonin has sleep inducing properties, and exerts important activities in the regulation of circadian rhythms. Melatonin is capable of phase shifting human circadian rhythms, of entraining free-running circadian rhythms, and of antagonizing phase shifts induced by nighttime exposure to light. Its effect on human reproduction is not completely clear, but stimulatory effects on gonadotropin secretion have been reported in the follicular phase of the menstrual cycle. Direct actions on ovarian cells and spermatozoa have been also documented. Beside these, new important actions for melatonin may be proved. Melatonin may exert protective effects on the cardiovascular system, by reducing the risk of atherosclerosis and hypertension, and may influence immune responses. Finally, by acting as an antioxidant, melatonin could be important in slowing the processes of ageing.
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Affiliation(s)
- A Cagnacci
- Institute of Obstetrics and Gynecology, University of Modena, Italy
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Cagnacci A, Volpe A. Influence of melatonin and photoperiod on animal and human reproduction. J Endocrinol Invest 1996; 19:382-411. [PMID: 8844459 DOI: 10.1007/bf03344974] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A Cagnacci
- Istituto di Fisiopatologia della Riproduzione Umana, Universitá di Modena, Italy
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Valenciano AI, Alonso-Gómez AL, De Pedro N, Alonso-Bedate M, Delgado MJ. Serotonin N-acetyltransferase activity as a target for temperature in the regulation of melatonin production by frog retina. Pflugers Arch 1994; 429:153-9. [PMID: 7892099 DOI: 10.1007/bf00374306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The adaptive mechanisms of serotonin N-acetyltransferase (NAT) activity in the regulation of melatonin synthesis in frog retina in the face of chronic and acute temperature changes have been investigated. We performed thermal acclimation experiments to test different environmental temperatures at two seasons of the year (summer and winter), followed by the set-up of an eyecup culture system to investigate the acute effects of temperature on NAT activity and melatonin production daily rhythms. Low temperature induced a significant increase in NAT activity, independent of both the time of the photocycle (midday or midnight) and the season of the year (winter or summer). Acute cold-induced stimulation of NAT activity may be associated with lower decreases in the enzyme synthesis rate, rather than decreases in the degradation rate. In contrast, acclimation to warm temperature (25 degrees C) stimulated ocular melatonin production. Nocturnal melatonin production in eyecups cultured at 25 degrees C was significantly higher than in eyecups cultured at 5 degrees C. We suggest that this discrepancy in thermal regulation of melatonin synthesis can be justified by a seasonal variation in serotonin content within the photoreceptor cells, which determines the thermal response of melatonin production through changes in NAT kinetics.
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Affiliation(s)
- A I Valenciano
- Facultad de Biología, Universidad Complutense, Madrid, Spain
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Abstract
Accumulated information shows that, besides its role in the timing of seasonal reproduction, melatonin also plays an important role in seasonal thermoregulatory adjustments of animals including torpor and hibernation. Furthermore, melatonin has a crucial role in circadian thermoregulatory adjustments of body temperature (Tb). Melatonin appears to send signals to the preoptic area of anterior hypothalamus (PoAH) where it adjusts the set point of Tb consistent with the metabolic rate of the animal. This new function for melatonin as a transducer mediating information about energy balance has been suggested in this review. Melatonin also adjusts the activity of the biological clock in vertebrates.
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Affiliation(s)
- S Saarela
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio 78284-7762
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