Evaluation of gene expression in human lymphocytes activated in the presence of melatonin

Use of Melatonin in Cancer Treatment: Where Are We?

Cancer represents a large group of diseases accounting for nearly 10 million deaths each year. Various treatment strategies, including surgical resection combined with chemotherapy, radiotherapy, and immunotherapy, have been applied for cancer treatment. However, the outcomes remain largely unsatisfying. Melatonin, as an endogenous hormone, is associated with the circadian rhythm moderation. Many physiological functions of melatonin besides sleep–wake cycle control have been identified, such as antioxidant, immunomodulation, and anti-inflammation. In recent years, an increasing number of studies have described the anticancer effects of melatonin. This has drawn our attention to the potential usage of melatonin for cancer treatment in the clinical setting, although huge obstacles still exist before its wide clinical administration is accepted. The exact mechanisms behind its anticancer effects remain unclear, and the specific characters impede its in vivo investigation. In this review, we will summarize the latest advances in melatonin studies, including its chemical properties, the possible mechanisms for its anticancer effects, and the ongoing clinical trials. Importantly, challenges for the clinical application of melatonin will be discussed, accompanied with our perspectives on its future development. Finally, obstacles and perspectives of using melatonin for cancer treatment will be proposed. The present article will provide a comprehensive foundation for applying melatonin as a preventive and therapeutic agent for cancer treatment.

The effect of a complex of melatonin, aluminum oxide and polymethylsiloxane on the cellular composition of the mice spleen kept in round-the-clock lighting conditions

It is known that the circadian rhythm of melatonin production depends on the intensity of illumination. Violation of the light regime leads to suppression of melatonin synthesis and the development of desynchronosis, which increases the risk of developing a number of pathologies. In this regard, it is relevant to search for opportunities to restore disturbed circadian rhythms and, especially, to correct immune dysfunctions that occur in these situations.The aim of this study was to examine the effect of a complex of melatonin, aluminum oxide and polymethylsiloxane on the lymphocytes of the spleen of mice kept under round-the-clock lighting.Materials and methods. Mice of the C57Bl/6J line were kept under round-the-clock lighting for 14 days, against which they were intragastrically injected with distilled water, aluminum oxide with polydimethylsiloxane, melatonin and a complex of melatonin, aluminum oxide and polymethylsiloxane (a new drug developed by the Research Institute of Clinical and Experimental Lymphology – Branch of the Federal Research Center Institute of Cytology and Genetics SB RAS; Patent of Russian Federation No. 2577580, 2016), represented by a complex of porous material (aluminum oxide with polydimethylsiloxane) and melatonin, immobilized in the pores, from which it is gradually released in a liquid medium. Intact animals kept under the light regime of ST 12/12 and under round-the-clock lighting served as a control. Immunophenotyping of spleen B- and T-lymphocytes was performed on a flow cytofluorimeter with monoclonal antibodies APC CD3 and FITC CD19. For studying the distribution of cells by stages of the cell cycle in splenocytes, the amount of intracellular DNA was measured by the level of inclusion of propidium iodide.Results. Flow cytometry of the distribution of B- and T-lymphocytes of the spleen in male mice of the C57Bl/6J line kept under round-the-clock lighting conditions (KO 24/0 h) revealed a decrease in the percentage of B-lymphocytes and an increase in the number of T-lymphocytes, compared with animals kept under standard lighting conditions (the light/dark photoperiod – 14/10 hours). The ratio of CD19+/CD3+ lymphocytes of the spleen in mice under the conditions of KO significantly decreases (1.5 times) compared to intact animals (p ≤ 0.001). The administration of pure and modified melatonin (Complex M) to animals kept under round-the-clock lighting conditions has an equally pronounced normalizing effect on the cellular composition of B- (CD19) and T- (CD3) lymphocytes of the spleen, bringing the values of the studied parameters to the control values of the intact animals (p ≤ 0.001) Round-the-clock lighting affects the proliferative potential of splenocytes, reducing the number of cells in the G2/M phase, compared with animals treated with melatonin (p ≤ 0.050). The introduction of melatonin leads to an increase in the percentage of cells in the G2/M phase relative to the placebo group (p ≤ 0.050). In the group of mice treated with Complex M, the greatest increase in cells at the S + G2/M phases and the highest percentage of cells at the G2/M phase were revealed compared to the placebo control group (p ≤ 0.050).Conclusion. The complex of melatonin, aluminum oxide and polymethylsiloxane has additional immunotropic properties in relation to the modifier molecule, which, apparently, are due to the joint immunostimulating effect of melatonin and the lymphostimulating effect of the sorbent. Melatonin in the composition of the complex shows its properties more stably.

Melatonin reduces inflammatory response in peripheral T helper lymphocytes from relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a neuroinflammatory disease of the central nervous system in which the immune system plays a central role. In particular, effector populations such as T helper (Th) 1, Th9, Th17, and Th22 cells are involved in disease development, whereas T regulatory cells (Tregs) are associated with the resolution of the disease. Melatonin levels are impaired in patients with MS, and exogenous melatonin ameliorates the disease in MS animal models by modulating the Th1/Th17/Treg responses and also improves quality of life and several symptoms in patients with MS. However, no study has examined melatonin's effect on T cells from relapsing-remitting MS (RR-MS) patients. Therefore, the objectives of the present study were to evaluate the effects of the in vitro administration of melatonin to peripheral blood mononuclear cells (PBMCs) from 64 RR-MS patients and 64 sex- and age-matched healthy subjects on Th1, Th9, Th17, Th22, and Treg responses and to analyze the expression of the melatonin effector/receptor system in these cells. Melatonin decreased Th1 and Th22 responses in patients, whereas it did not affect the Th17 and Treg subsets. Melatonin also promoted skewing toward a more protective cytokine microenvironment, as shown by an increased anti-inflammatory/Th1 ratio. Furthermore, for the first time, we describe the overexpression of the melatonin effector/receptor system in PBMCs from patients with MS; this alteration might be relevant to the disease because acetylserotonin O-methyltransferase expression significantly correlates with disease progression and T effector/regulatory responses in patients. Therefore, our data suggest that melatonin may be an effective treatment for MS.

Melatonin: buffering the immune system

Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

β-Thymosins and interstitial lung disease: study of a scleroderma cohort with a one-year follow-up

Background

β-thymosins play roles in cytoskeleton rearrangement, angiogenesis, fibrosis and reparative process, thus suggesting a possible involvement in the pathogenesis of systemic sclerosis. The aim of the study was to investigate the presence of thymosins β₄, β₄ sulfoxide, and β₁₀ in bronchoalveolar lavage fluid of scleroderma patients with interstitial lung disease and the relation of these factors with pulmonary functional and radiological parameters.

Methods

β-thymosins concentrations were determined by Reverse Phase-High Performance Liquid Chromatography-Electrospray-Mass Spectrometry in the bronchoalveolar lavage fluid of 46 scleroderma patients with lung involvement and of 15 controls.

Results

Thymosin β_4, β₄ sulfoxide, and β₁₀ were detectable in bronchoalveolar lavage fluid of patients and controls. Thymosin β₄ levels were significantly higher in scleroderma patients than in controls. In addition, analyzing the progression of scleroderma lung disease at one-year follow-up, we have found that higher thymosin β₄ levels seem to have a protective role against lung tissue damage. Thymosin β₄ sulfoxide levels were higher in the smokers and in the scleroderma patients with alveolitis.

Conclusions

We describe for the first time β-thymosins in bronchoalveolar lavage fluid and their possible involvement in the pathogenesis of scleroderma lung disease. Thymosin β₄ seems to have a protective role against lung tissue damage, while its oxidation product mirrors an alveolar inflammatory status.

A review of the multiple actions of melatonin on the immune system

This review summarizes the numerous observations published in recent years which have shown that one of the most significant of melatonin's pleiotropic effects is the regulation of the immune system. The overview summarizes the immune effects of pinealectomy and the association between rhythmic melatonin production and adjustments in the immune system as markers of melatonin's immunomodulatory actions. The effects of both in vivo and in vitromelatonin administration on non-specific, humoral, and cellular immune responses as well as on cellular proliferation and immune mediator production are presented. One of the main features that distinguishes melatonin from the classical hormones is its synthesis by a number of non-endocrine extrapineal organs, including the immune system. Herein, we summarize the presence of immune system-synthesized melatonin, its direct immunomodulatory effects on cytokine production, and its masking effects on exogenous melatonin action. The mechanisms of action of melatonin in the immune system are also discussed, focusing attention on the presence of membrane and nuclear receptors and the characterization of several physiological roles mediated by some receptor analogs in immune cells. The review focuses on melatonin's actions in several immune pathologies including infection, inflammation, and autoimmunity together with the relation between melatonin, immunity, and cancer.

Effects of exogenous melatonin--a review

The results of studies on the effect of pineal indole hormone melatonin on the life span of mice, rats, fruit flies, and worms are critically reviewed. In mice, long-term administration of melatonin was followed by an increase in their life span in 12 experiments and had no effect in 8 of 20 different experiments. In D. melanogaster, the supplementation of melatonin to the nutrient medium during developmental stages gave contradictory results, but when melatonin was added to food throughout the life span, an increase in the longevity of fruit flies has been observed. Melatonin decreased the survival of C. elegans but increased the clonal life span of planaria Paramecium tertaurelia. Available data suggest antioxidant and atherogenic effects of melatonin. Melatonin alone turned out to be neither toxic nor mutagenic in the Ames test and revealed clastogenic activity in high concentration in the COMET assay. Melatonin inhibits mutagenesis induced by irradiation and by indirect chemical mutagens and inhibits the development of spontaneous and chemical-induced tumors in mice and rats. Further studies and clinical trials are needed to verify that melatonin is both safe and has geroprotector efficacy for humans.