Exogenous Melatonin Up-Regulates Expression of CD62L by Lymphocytes in Aged Mice under Inflammatory and Non-Inflammatory Conditions

Signaling pathways in skin cancers and the protective functions of melatonin

Melatonin, a hormone primarily synthesized in the pineal gland, has an essential role in the regulation of various physiological processes, such as the sleep-wake cycle, immune function, and antioxidative responses. Emerging evidence suggests that melatonin also exerts significant protective effects against skin cancers, particularly melanoma and non-melanoma skin cancers. This review aims to provide a comprehensive overview of melatonin's multifaceted mechanisms of action in preventing and treating skin cancers, focusing on its antioxidant, photoprotective, and radioprotective properties. Melatonin's capability to modulate skin cancer's related key signaling pathways underscores its complex yet potent anticancer mechanisms. Furthermore, synergistic effects between melatonin and conventional oncology treatments, such as radiotherapy, chemotherapy, and targeted therapies, hold promise for improving treatment outcomes while mitigating adverse effects. However, while melatonin shows great potential as an adjunct in oncology treatment regimens, further research is needed to optimize its clinical applications and fully understand its safety profile and potential side effects. Overall, elucidating melatonin's role in skin cancer prevention and treatment represents a promising avenue for advancing cancer therapeutics and improving patient outcomes.

Cancer Metabolism as a Therapeutic Target and Review of Interventions

Cancer is amenable to low-cost treatments, given that it has a significant metabolic component, which can be affected through diet and lifestyle change at minimal cost. The Warburg hypothesis states that cancer cells have an altered cell metabolism towards anaerobic glycolysis. Given this metabolic reprogramming in cancer cells, it is possible to target cancers metabolically by depriving them of glucose. In addition to dietary and lifestyle modifications which work on tumors metabolically, there are a panoply of nutritional supplements and repurposed drugs associated with cancer prevention and better treatment outcomes. These interventions and their evidentiary basis are covered in the latter half of this review to guide future cancer treatment.

Inflammation Control and Immunotherapeutic Strategies in Comprehensive Cancer Treatment

Tumor growth and expansion are determined by the immunological tumor microenvironment (TME). Typically, early tumorigenic stages are characterized by the immune system not responding or weakly responding to the tumor. However, subsequent tumorigenic stages witness the tumor promoting its growth and metastasis by stimulating tumor-protective (pro-tumor) inflammation to suppress anti-tumor immune responses. Here, we propose the pivotal role of inflammation control in a successful anti-cancer immunotherapy strategy, implying that available and novel immunotherapeutic modalities such as inflammation modulation, antibody (Ab)-based immunostimulation, drug-mediated immunomodulation, cancer vaccination as well as adoptive cell immunotherapy and donor leucocyte transfusion could be applied in cancer patients in a synergistic manner to amplify each other's clinical effects and achieve robust anti-tumor immune reactivity. In addition, the anti-tumor effects of immunotherapy could be enhanced by thermal and/or oxygen therapy. Herein, combined immune-based therapy could prove to be beneficial for patients with advanced cancers, as aiming to provide long-term tumor cell/mass dormancy by restraining compensatory proliferation of surviving cancer cells observed after traditional anti-cancer interventions such as surgery, radiotherapy, and metronomic (low-dose) chemotherapy. We propose the Inflammatory Prognostic Score based on the blood levels of C-reactive protein and lactate dehydrogenase as well as the neutrophil-to-lymphocyte ratio to effectively monitor the effectiveness of comprehensive anti-cancer treatment.

Tumor Microenvironment and Metabolism: Role of the Mitochondrial Melatonergic Pathway in Determining Intercellular Interactions in a New Dynamic Homeostasis

There is a growing interest in the role of alterations in mitochondrial metabolism in the pathoetiology and pathophysiology of cancers, including within the array of diverse cells that can form a given tumor microenvironment. The 'exhaustion' in natural killer cells and CD8+ t cells as well as the tolerogenic nature of dendritic cells in the tumor microenvironment seems determined by variations in mitochondrial function. Recent work has highlighted the important role played by the melatonergic pathway in optimizing mitochondrial function, limiting ROS production, endogenous antioxidants upregulation and consequent impacts of mitochondrial ROS on ROS-dependent microRNAs, thereby impacting on patterned gene expression. Within the tumor microenvironment, the tumor, in a quest for survival, seeks to 'dominate' the dynamic intercellular interactions by limiting the capacity of cells to optimally function, via the regulation of their mitochondrial melatonergic pathway. One aspect of this is the tumor's upregulation of kynurenine and the activation of the aryl hydrocarbon receptor, which acts to metabolize melatonin and increase the N-acetylserotonin/melatonin ratio, with effluxed N-acetylserotonin acting as a brain-derived neurotrophic factor (BDNF) mimic via its activation of the BDNF receptor, TrkB, thereby increasing the survival and proliferation of tumors and cancer stem-like cells. This article highlights how many of the known regulators of cells in the tumor microenvironment can be downstream of the mitochondrial melatonergic pathway regulation. Future research and treatment implications are indicated.

Psycho-Neuro-Endocrine-Immunology: A Role for Melatonin in This New Paradigm

Psychoneuroendocrinoimmunology is the area of study of the intimate relationship between immune, physical, emotional, and psychological aspects. This new way of studying the human body and its diseases was initiated in the last century’s first decades. However, the molecules that participate in the communication between the immune, endocrine, and neurological systems are still being discovered. This paper aims to describe the development of psychoneuroendocrinoimmunology, its scopes, limitations in actual medicine, and the extent of melatonin within it.

Insight of Melatonin: The Potential of Melatonin to Treat Bacteria-Induced Mastitis

Bovine mastitis is a common inflammatory disease, mainly induced by bacterial pathogens, such as Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae. Mastitis has negative effects on the production and quality of milk, resulting in huge economic losses. Melatonin, which is synthesized and secreted by the pineal gland and other organs, is ubiquitous throughout nature and has different effects on different tissues. Melatonin is crucial in modulating oxidative stress, immune responses, and cell autophagy and apoptosis, via receptor-mediated or receptor-independent signaling pathways. The potent antioxidative and anti-inflammatory activities of melatonin and its metabolites suggest that melatonin can be used to treat various infections. This article reviews the potential for melatonin to alleviate bovine mastitis through its pleiotropic effect on reducing oxidative stress, inhibiting pro-inflammatory cytokines, and regulating the activation of NF-κB, STATs, and their cascade reactions. Therefore, it is promising that melatonin supplementation may be an alternative to antibiotics for the treatment of bovine mastitis.

Melatonin and REGN-CoV2 combination as a vaccine adjuvant for Omicron variant of SARS-CoV-2

The omicron variant (B.529) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in late 2021, caused panic worldwide due to its contagiousness and multiple mutations in the spike protein compared to the Delta variant (B.617.2). There is currently no specific antiviral available to treat Coronavirus disease 2019 (COVID-19). However, studies on neutralizing monoclonal antibodies (mAb) developed to fight COVID-19 are growing and gaining traction. REGN-COV2 (Regeneron or imdevimab-casirivimab combination), which has been shown in recent studies to be less affected by Omicron's RBD (receptor binding domain) mutations among other mAb cocktails, plays an important role in adjuvant therapy against COVID-19. On the other hand, it is known that melatonin, which has antioxidant and immunomodulatory effects, can prevent a possible cytokine storm, and other severe symptoms that may develop in the event of viral invasion. Along with all these findings, we believe it is crucial to evaluate the use of melatonin with REGN-COV2, a cocktail of mAbs, as an adjuvant in the treatment and prevention of COVID-19, particularly in immunocompromised and elderly patients.

The antinociceptive mechanisms of melatonin: role of L-arginine/nitric oxide/cyclic GMP/KATP channel signaling pathway

Pain is one of the most common medical challenges, reducing life quality. Despite the progression in pain management, it has remained a clinical challenge, which raises the need for investigating novel antinociceptive drugs with correspondence signaling pathways. Besides, the precise antinociceptive mechanisms of melatonin are not revealed. Accordingly, owing to the critical role of L-arginine/nitric oxide (NO)/cyclic GMP (cGMP)/KATP in the antinociceptive responses of various analgesics, the role of this signaling pathway is evaluated in the antinociceptive effects of melatonin. Male NMRI mice were intraperitoneally pretreated with the injection of L-arginine (NO precursor, 100 mg/kg), N(gamma)-nitro-L-arginine methyl ester [L-NAME, NO synthase (NOS) inhibitor, 30 mg/kg], S-nitroso-N-acetylpenicillamine (SNAP, NO donor, 1 mg/kg), sildenafil (phosphodiesterase inhibitor, 0.5 mg/kg), and glibenclamide (KATP channel blocker, 10 mg/kg) alone and before the administration of the most effective dose of melatonin amongst the intraperitoneal doses of 50, 100, and 150 mg/kg. The formalin test (2%, 25 µL, intra-plantarly) was done following the melatonin administration, then the nociceptive responses of mice were evaluated during the early phase for 5 min and the late phase for 15 min. The results showed that 100 mg/kg dose of melatonin carried out the most antinociceptive effects. While the antinociceptive effect of melatonin was increased by L-arginine, SNAP, and sildenafil, it was significantly reduced by L-NAME and glibenclamide in both phases of the formalin test, with no relation to the sedative effects of melatonin evaluated by the inclined plane test. In conclusion, the antinociceptive effect of melatonin is mediated through the L-arginine/NO/cGMP/KATP pathway.

Role of Melatonin in Angiotensin and Aging

The cellular utilization of oxygen leads to the generation of free radicals in organisms. The accumulation of these free radicals contributes significantly to aging and several age-related diseases. Angiotensin II can contribute to DNA damage through oxidative stress by activating the NAD(P)H oxidase pathway, which in turn results in the production of reactive oxygen species. This radical oxygen-containing molecule has been linked to aging and several age-related disorders, including renal damage. Considering the role of angiotensin in aging, melatonin might relieve angiotensin-II-induced stress by enhancing the mitochondrial calcium uptake 1 pathway, which is crucial in preventing the mitochondrial calcium overload that may trigger increased production of reactive oxygen species and oxidative stress. This review highlights the role and importance of melatonin together with angiotensin in aging and age-related diseases.

The 15-Months Clinical Experience of SARS-CoV-2: A Literature Review of Therapies and Adjuvants

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the coronavirus disease of 2019 (COVID-19) that emerged in December 2019 in Wuhan, China, and rapidly spread worldwide, with a daily increase in confirmed cases and infection-related deaths. The World Health Organization declared a pandemic on the 11th of March 2020. COVID-19 presents flu-like symptoms that become severe in high-risk medically compromised subjects. The aim of this study was to perform an updated overview of the treatments and adjuvant protocols for COVID-19.

METHODS

A systematic literature search of databases was performed (MEDLINE PubMed, Google Scholar, UpToDate, Embase, and Web of Science) using the keywords: "COVID-19", "2019-nCoV", "coronavirus" and "SARS-CoV-2" (date range: 1 January 2019 to 31st October 2020), focused on clinical features and treatments.

RESULTS

The main treatments retrieved were antivirals, antimalarials, convalescent plasma, immunomodulators, corticosteroids, anticoagulants, and mesenchymal stem cells. Most of the described treatments may provide benefits to COVID-19 subjects, but no one protocol has definitively proven its efficacy.

CONCLUSIONS

While many efforts are being spent worldwide in research aimed at identifying early diagnostic methods and evidence-based effective treatments, mass vaccination is thought to be the best option against this disease in the near future.

Melatonin Downregulates PD-L1 Expression and Modulates Tumor Immunity in KRAS-Mutant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) patients harboring a KRAS mutation have unfavorable therapeutic outcomes with chemotherapies, and the mutation also renders tolerance to immunotherapies. There is an unmet need for a new strategy for overcoming immunosuppression in KRAS-mutant NSCLC. The recently discovered role of melatonin demonstrates a wide spectrum of anticancer impacts; however, the effect of melatonin on modulating tumor immunity is largely unknown. In the present study, melatonin treatment significantly reduced cell viability accompanied by inducing cell apoptosis in KRAS-mutant NSCLC cell lines including A549, H460, and LLC1 cells. Mechanistically, we found that lung cancer cells harboring the KRAS mutation exhibited a higher level of programmed death ligand 1 (PD-L1). However, treatment with melatonin substantially downregulated PD-L1 expressions in both the presence and absence of interferon (IFN)-γ stimulation. Moreover, KRAS-mutant lung cancer cells exhibited higher Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) levels, and PD-L1 expression was positively correlated with YAP and TAZ in lung cancer cells. Treatment with melatonin effectively suppressed YAP and TAZ, which was accompanied by downregulation of YAP/TAZ downstream gene expressions. The combination of melatonin and an inhibitor of YAP/TAZ robustly decreased YAP and PD-L1 expressions. Clinical analysis using public databases revealed that PD-L1 expression was positively correlated with YAP and TAZ in patients with lung cancer, and PD-L1 overexpression suggested poor survival probability. An animal study further revealed that administration of melatonin significantly inhibited tumor growth and modulated tumor immunity in a syngeneic mouse model. Together, our data revealed a novel antitumor mechanism of melatonin in modulating the immunosuppressive tumor microenvironment by suppressing the YAP/PD-L1 axis and suggest the therapeutic potential of melatonin for treating NSCLC.

Melatonin in Cancer Treatment: Current Knowledge and Future Opportunities

Melatonin is a pleotropic molecule with numerous biological activities. Epidemiological and experimental studies have documented that melatonin could inhibit different types of cancer in vitro and in vivo. Results showed the involvement of melatonin in different anticancer mechanisms including apoptosis induction, cell proliferation inhibition, reduction in tumor growth and metastases, reduction in the side effects associated with chemotherapy and radiotherapy, decreasing drug resistance in cancer therapy, and augmentation of the therapeutic effects of conventional anticancer therapies. Clinical trials revealed that melatonin is an effective adjuvant drug to all conventional therapies. This review summarized melatonin biosynthesis, availability from natural sources, metabolism, bioavailability, anticancer mechanisms of melatonin, its use in clinical trials, and pharmaceutical formulation. Studies discussed in this review will provide a solid foundation for researchers and physicians to design and develop new therapies to treat and prevent cancer using melatonin.

SARS-CoV-2 Disease Adjuvant Therapies and Supplements Breakthrough for the Infection Prevention

The SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is a high-risk viral agent involved in the recent pandemic stated worldwide by the World Health Organization. The infection is correlated to a severe systemic and respiratory disease in many cases, which is clinically treated with a multi-drug pharmacological approach. The purpose of this investigation was to evaluate through a literature overview the effect of adjuvant therapies and supplements for the SARS-CoV-2 infection. The research has analyzed the advantage of the EK1C4, by also assessing the studies on the resveratrol, vitamin D, and melatonin as adjuvant supplements for long hauler patients' prognosis. The evaluated substances reported important benefits for the improvement of the immune system and as a potential inhibitor molecules against SARS-CoV-2, highlighting the use of sartans as therapy. The adjuvant supplements seem to create an advantage for the healing of the long hauler patients affected by chronic symptoms of constant chest and heart pain, intestinal disorders, headache, difficulty concentrating, memory loss, and tachycardia.

Clinically feasible and prospective immunotherapeutic interventions in multidirectional comprehensive treatment of cancer

INTRODUCTION

The immune system is able to exert both tumor-destructive and tumor-protective functions. Immunotherapeutic technologies aim to enhance immune-based anti-tumor activity and (or) weaken tumor-protective immunity.

AREAS COVERED

Cancer vaccination, antibody (Ab)-mediated cytotoxicity, Ab-based checkpoint molecule inhibition, Ab-based immunostimulation, cytokine therapy, oncoviral therapy, drug-mediated immunostimulation, exovesicular therapy, anti-inflammatory therapy, neurohormonal immunorehabilitation, metabolic therapy, as well as adoptive cell immunotherapy, could be coherently used to synergize and amplify each other in achieving robust anti-cancer responses in cancer patients. Tumor-specific immunotherapy applied at early stages is capable of eliminating remaining tumor cells after surgery, thus preventing the development of minimal residual disease. Patients with advanced disease stages could benefit from combined immunotherapy, which would be aimed at providing tumor cell/mass dormancy. Traditional therapeutic anti-cancer interventions (chemoradiotherapy, hyperthermia, anti-hormonal therapy) could significantly enhance tumor sensitivity to anti-cancer immunotherapy. It is important that lower-dose (metronomic) chemotherapy regimens, which are well-tolerated by normal cells, could advance immune-mediated control over tumor growth.

EXPERT OPINION

We envisage that combined immunotherapy regimens in the context of traditional treatment could become the mainstream modality for treating cancers in all phases of the tumorigenesis. The effectiveness of the anti-cancer treatment could be monitored by the following blood parameters: C-reactive protein, lactate dehydrogenase, and neutrophil-to-lymphocyte ratio.

Role of melatonin in the treatment of COVID-19; as an adjuvant through cluster differentiation 147 (CD147)

COVID-19 caused by the SARS-CoV-2 outbreak quickly has turned into a pandemic. However, no specific antiviral agent is yet available. In this communication, we aimed to evaluate the significance of CD147 protein and the potential protective effect of melatonin that is mediated by this protein in COVID-19. CD147 is a glycoprotein that is responsible for the cytokine storm in the lungs through the mediation of viral invasion. Melatonin use previously was shown to reduce cardiac damage by blocking the CD147 activity. Hence, melatonin, a safe drug, may prevent severe symptoms, reduce symptom severity and the adverse effects of the other antiviral drugs in COVID-19 patients. In conclusion, the use of melatonin, which is reduced in the elderly and immune-compromised patients, should be considered as an adjuvant through its CD147 suppressor and immunomodulatory effect.

Systematic Study of the Immune Components after Ischemic Stroke Using CyTOF Techniques

Stroke induces a robust inflammatory response. However, it still lacks a systematic view of the various immune cell types due to the limited numbers of fluorophore used in the traditional FACS technique. In our current study, we utilized the novel technique mass cytometry (CyTOF) to analyze multiple immune cell types. We detected these immune cells from the ischemic brain, peripheral blood, spleen, and bone marrow at different time courses after stroke. Our data showed (1) dynamic changes in the immune cell numbers in the ischemic brain and peripheral organs. (2) The expression levels of cell surface markers indicate the inflammation response status after stroke. Interestingly, CD62L, a key adhesion molecule, regulates the migration of leukocytes from blood vessels into secondary lymphoid tissues and peripheral tissues. (3) A strong leukocyte network across the brain and peripheral immune organs was identified using the R program at day 1 after ischemia, suggesting that the peripheral immune cells dramatically migrated into the ischemic areas after stroke. This study provides a systematic, wide view of the immune components in the brain and peripheral organs for a deep understanding of the immune response after ischemic stroke.

Clinical impact of melatonin on breast cancer patients undergoing chemotherapy; effects on cognition, sleep and depressive symptoms: A randomized, double-blind, placebo-controlled trial

This randomized, double-blinded, placebo-controlled trial tested the hypothesis that 20mg of melatonin before and during the first cycle of adjuvant chemotherapy for breast cancer (ACBC) reduced the side effects associated with cognitive impairment. We evaluated the effects of melatonin on cognition, depressive symptoms and sleep quality, and whether these effects were related to serum levels of Brain Derived Neurotrophic Factor (BDNF) and its receptor, tropomyosin kinase B (TrkB). Thirty-six women were randomly assigned to receive melatonin or placebo for 10 days. To evaluate cognitive performance, we used the Trail-Making-Test Parts A and B (A-B), Rey Auditory-Verbal Learning Test (RAVLT), Controlled Oral Word Association Test (COWAT) and an inhibitory task type Go / No-Go. Our results revealed that melatonin improved executive function on TMT scores, enhanced episodic memory (immediate and delayed) and recognition on RAVLT, and increased verbal fluency in the orthographic COWAT. The TMT-A-B(A-B) were negatively correlated with baseline levels of TrkB and BDNF, respectively. At the end of treatment, changes in TrkB and BDNF were inversely associated with depressive symptoms and sleep quality, but not with the TMT scores. These results suggest a neuroprotective effect of melatonin to counteract the adverse effects of ACBC on cognitive function, sleep quality and depressive symptoms.