Melatonin and non-small cell lung cancer: new insights into signaling pathways

IL-17 induces NSCLC cell migration and invasion by elevating MMP19 gene transcription and expression through the interaction of p300-dependent STAT3-K631 acetylation and its Y705-phosphorylation

The cancer cell metastasis is a major death reason for patients with non-small cell lung cancer (NSCLC). Although researchers have disclosed that interleukin 17 (IL-17) can increase matrix metalloproteinases (MMPs) induction causing NSCLC cell metastasis, the underlying mechanism remains unclear. In the study, we found that IL-17 receptor A (IL-17RA), p300, p-STAT3, Ack-STAT3, and MMP19 were up-regulated both in NSCLC tissues and NSCLC cells stimulated with IL-17. p300, STAT3 and MMP19 overexpression or knockdown could raise or reduce IL-17-induced p-STAT3, Ack-STAT3 and MMP19 level as well as the cell migration and invasion. Mechanism investigation revealed that STAT3 and p300 bound to the same region (-544 to -389 nt) of MMP19 promoter, and p300 could acetylate STAT3-K631 elevating STAT3 transcriptional activity, p-STAT3 or MMP19 expression and the cell mobility exposed to IL-17. Meanwhile, p300-mediated STAT3-K631 acetylation and its Y705-phosphorylation could interact, synergistically facilitating MMP19 gene transcription and enhancing cell migration and invasion. Besides, the animal experiments exhibited that the nude mice inoculated with NSCLC cells by silencing p300, STAT3 or MMP19 gene plus IL-17 treatment, the nodule number, and MMP19, Ack-STAT3, or p-STAT3 production in the lung metastatic nodules were all alleviated. Collectively, these outcomes uncover that IL-17-triggered NSCLC metastasis involves up-regulating MMP19 expression via the interaction of STAT3-K631 acetylation by p300 and its Y705-phosphorylation, which provides a new mechanistic insight and potential strategy for NSCLC metastasis and therapy.

Significance of Melatonin in the Regulation of Circadian Rhythms and Disease Management

Melatonin, the 'hormone of darkness' is a neuronal hormone secreted by the pineal gland and other extra pineal sites. Responsible for the circadian rhythm and seasonal behaviour of vertebrates and mammals, melatonin is responsible for regulating various physiological conditions and the maintenance of sleep, body weight and the neuronal activities of the ocular sites. With its unique amphiphilic structure, melatonin can cross the cellular barriers and elucidate its activities in the subcellular components, including mitochondria. Melatonin is a potential scavenger of oxygen and nitrogen-reactive species and can directly obliterate the ROS and RNS by a receptor-independent mechanism. It can also regulate the pro- and anti-inflammatory cytokines in various pathological conditions and exhibit therapeutic activities against neurodegenerative, psychiatric disorders and cancer. Melatonin is also found to show its effects on major organs, particularly the brain, liver and heart, and also imparts a role in the modulation of the immune system. Thus, melatonin is a multifaceted candidate with immense therapeutic potential and is still considered an effective supplement on various therapies. This is primarily due to rectification of aberrant circadian rhythm by improvement of sleep quality associated with risk development of neurodegenerative, cognitive, cardiovascular and other metabolic disorders, thereby enhancing the quality of life.

Unraveling the impact of melatonin treatment: Oxidative stress, metabolic responses, and morphological changes in HuH7.5 hepatocellular carcinoma cells

In addition to its highly aggressive nature and late diagnosis, hepatocellular carcinoma (HCC) does not respond effectively to available chemotherapeutic agents. The search is on for an ideal and effective compound with low cost and minimal side effects that can be used as an adjunct to chemotherapeutic regimens. One of the mechanisms involved in the pathology of HCC is the oxidative stress, which plays a critical role in tumor survival and dissemination. Our group has already demonstrated the antitumor potential of melatonin against HuH 7.5 cells. In the present study, we focused on the effects of melatonin on oxidative stress parameters and their consequences on cell metabolism. HuH 7.5 cells were treated with 2 and 4 mM of melatonin for 24 and 48 h. Oxidative stress biomarkers, antioxidant enzyme, mitochondrial membrane potential, formation of lipid bodies and autophagic vacuoles, cell cycle progression, cell death rate and ultrastructural cell alterations were evaluated. The treatment with melatonin increased oxidative stress biomarkers and reduced antioxidant enzyme activities of HuH 7.5 cells. Additionally, melatonin treatment damaged the mitochondrial membrane and increased lipid bodies and autophagic vacuole formation. Melatonin triggered cell cycle arrest and induced cell death by apoptosis. Our results indicate that the treatment of HuH 7.5 cells with melatonin impaired antioxidant defense systems, inhibited cell cycle progression, and caused metabolic stress, culminating in tumor cell death.

Beyond the genome: lncRNAs as regulators of the PI3K/AKT pathway in lung cancer

Lung cancer is a prevalent and devastating disease, representing a significant global health burden. Despite advancements in therapeutic strategies, the molecular mechanisms underlying its pathogenesis remain incompletely understood. Lung cancer typically displays the deregulated activity of the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway, which is vital for cell proliferation, survival, and metastasis. Emerging evidence suggests that long non-coding RNA (lncRNAs) can modulate the PI3K/AKT pathway, offering new insights into lung cancer biology and potential therapeutic opportunities. These lncRNA act as either oncogenes, promoting pathway activation, or tumour suppressors, attenuating pathway signalling. The dysregulation of lncRNA is associated with various cellular processes, including apoptosis, cell cycle control, epithelial-mesenchymal transition (EMT), and angiogenesis, ultimately influencing lung cancer growth and metastasis. The development of novel therapeutic strategies, such as small interfering RNAs (siRNAs), antisense oligonucleotides, and CRISPR/Cas9-mediated gene editing, holds promise for restoring lncRNAs dysregulation and re-establishing the equilibrium of the PI3K/AKT pathway. The emerging role of lncRNAs as regulators of the PI3K/AKT pathway sheds new light on the complex molecular landscape of lung cancer. Understanding the interplay between lncRNA and the PI3K/AKT pathway could lead to the identification of novel biomarkers for prognosis and therapeutic targets for precision medicine. The potential of lncRNAs-based therapeutics may pave the way for more effective and personalized treatment approaches in lung cancer and potentially other malignancies with dysregulated PI3K/AKT signalling. This review aims to explore the emerging role of lncRNAs as key regulators of the PI3K/AKT pathway in lung cancer.

An RNA-seq transcriptome analysis for investigating the anti-lung cancer activity of medicinal Cuscuta chinensis Lam plant

Cuscuta chinensis Lam. is a traditional medicinal herb used to treat female sterility and male reproductive system disorders. However, the anti-lung cancer properties of Cuscuta chinensis Lam. and possible molecular mechanisms have yet to be explored. Thus, the study’s main purpose was to evaluate in vitro and in vivo anti-lung cancer properties of C. chinensis water extract (CLW) in human lung adenocarcinomas and the underlying molecular mechanism involved. Our results demonstrated that CLW caused a significant inhibition of cell viability and induced G1 cycle arrest in lung cancer cells. Furthermore, RNA-seq transcriptome analysis revealed 602 common genes with a significant expression in A549 and H1650 cells under CLW treatment. Functional enrichment analysis suggested that these common genes regulated by CLW mainly involve lung cancer cell proliferation, metastases and apoptosis processes. In addition, forty-six common genes (> 2-fold change) regulated by CLW in A549 and H1650 cells were selected for further validation. In vitro quantitative real-time PCR results confirmed that twelve genes were up-regulated, and four genes were down-regulated in A549 and H1650 cells. The in vivo experiment demonstrated CLW could significantly decrease tumour volume and tumour weight of mice compared with the control group. Moreover, in vivo quantitative real-time PCR results revealed that C11orf96, FGFBP1, FOSB and NPTX1 genes were up-regulated and EGR1, GBP4 and MAP2K6 genes were down-regulated in tumour tissues compared with the control group. These data strongly suggest that CLW could be developed as an efficacious drug for lung cancer treatment.

Combinatorial effects of melatonin and paclitaxel differ depending on the treatment scheme in colorectal cancer in vitro

AIMS

Colorectal carcinoma (CRC) is the third most prevalent cancer with high mortality. Besides regulating the circadian rhythm, melatonin (MTN) exerts anticancer activities. Paclitaxel (PTX) is successful against different malignancies, however, acquired resistance and variability in patient response restrict its use. mTOR and MAPK pathways are often deregulated in human cancers. We aimed to investigate whether MTN enhances or sensitizes the chemotherapeutic activity of PTX and if so, determine the underlying possible mechanisms in CRC in vitro.

MAIN METHODS

Antiproliferative and cytotoxic activities of PTX and MTN were assessed alone and in combination, as well as with different treatment regimens (renewal or replacement of the treatment after 24 h), up to 48 h. Apoptosis, viability and autophagy were assessed by flow cytometry. mTOR and MAPK pathway activities were investigated by immunoblotting.

KEY FINDINGS

Both drugs reduced cell viability in a dose-dependent manner at 24 and 48 h. Only the highest dose of MTN (500 μM) potentiated the cytotoxicity of PTX (50 nM). Replacement of PTX after 24 h with MTN was superior in reducing cell viability than vice versa via apoptosis induction. Renewal of MTN treatment every 24 h reduced autophagy compared to the control group, while other treatments did not alter the autophagic activity. A 24 h MTN treatment followed by 24 h PTX treatment increased S6 phosphorylation in a mTOR-independent manner and increased Erk1/2 phosphorylation.

SIGNIFICANCE

The present study suggests that sequential treatment with MTN and PTX distinctly affect apoptosis and cytotoxicity via regulating mTOR and MAPK pathways differentially in CRC.

Melatonin is a potential oncostatic agent to inhibit HepG2 cell proliferation through multiple pathways

Context

Chemotherapy is a cornerstone in the treatment of hepatocellular carcinoma (HCC). Melatonin is a pineal hormone that targets various cancers, however, its antitumor pathways are still not fully elucidated.

Objective

This study investigated melatonin's antitumor molecular mechanisms to inhibit the proliferation of HepG2 cells.

Materials and methods

HepG2 Cells were classified into cells without treatment as a control group and cells treated with melatonin (5.4 mmol/L) for 48 h. Proliferating cell nuclear antigen (PCNA) and marker of proliferation Ki-67 were estimated using immunohistochemical analysis. Apoptosis and cell cycle were evaluated using flow cytometric analysis. Apoptotic markers were detected using RT-qPCR assay. Antioxidants and oxidative stress biomarkers were performed using a colorimetric assay.

Results

Melatonin produced a remarkable steady decrease in the viability of HepG2 cells at a concentration range between 5-20 mmol/L. Melatonin suppressed cell proliferation in the G2/M phase of the cell cycle (34.97 ± 0.92%) and induced apoptosis (12.43 ± 0.73%) through up-regulating p21 and p53 that was confirmed by the reduction of PCNA and Ki-67 expressions. Additionally, melatonin repressed angiogenesis evidenced by the down-regulation of angiopoietin-2, vascular endothelial growth factor receptor-2 expressions (0.42-fold change), and the level of CD133. Moreover, melatonin augmented the oxidative stress manifested by a marked increase of 4-hydroxynonenal levels with a reduction of glutathione content and superoxide dismutase activity.

Discussion and conclusion

Melatonin inhibits proliferation and angiogenesis and induced apoptosis and oxidative stress in HepG2 cells. These results indicate the oncostatic effectiveness of melatonin on liver cancer.

Genetic Variants of CLEC4E and BIRC3 in Damage-Associated Molecular Patterns-Related Pathway Genes Predict Non-Small Cell Lung Cancer Survival

Accumulating evidence supports a role of various damage-associated molecular patterns (DAMPs) in progression of lung cancer, but roles of genetic variants of the DAMPs-related pathway genes in lung cancer survival remain unknown. We investigated associations of 18,588 single-nucleotide polymorphisms (SNPs) in 195 DAMPs-related pathway genes with non-small cell lung cancer (NSCLC) survival in a subset of genotyping data for 1,185 patients from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and validated the findings in another independent subset of genotyping data for 984 patients from Harvard Lung Cancer Susceptibility Study. We performed multivariate Cox proportional hazards regression analysis, followed by expression quantitative trait loci (eQTL) analysis, Kaplan-Meier survival analysis and bioinformatics functional prediction. We identified that two SNPs (i.e., CLEC4E rs10841847 G>A and BIRC3 rs11225211 G>A) were independently associated with NSCLC overall survival, with adjusted allelic hazards ratios of 0.89 (95% confidence interval=0.82-0.95 and P=0.001) and 0.82 (0.73-0.91 and P=0.0003), respectively; so were their combined predictive alleles from discovery and replication datasets (P_trend=0.0002 for overall survival). We also found that the CLEC4E rs10841847 A allele was associated with elevated mRNA expression levels in normal lymphoblastoid cells and whole blood cells, while the BIRC3 rs11225211 A allele was associated with increased mRNA expression levels in normal lung tissues. Collectively, these findings indicated that genetic variants of CLEC4E and BIRC3 in the DAMPs-related pathway genes were associated with NSCLC survival, likely by regulating the mRNA expression of the corresponding genes.

Melatonin inhibits proliferation, migration, and invasion by inducing ROS-mediated apoptosis via suppression of the PI3K/Akt/mTOR signaling pathway in gallbladder cancer cells

BACKGROUND

Melatonin is an indolic compound mainly secreted by the pineal gland and plays a vital role in the regulation of circadian rhythms and cancer therapy. However, the effects of melatonin in gallbladder cancer (GBC) and the related mechanism remain unknown.

METHODS

In this study, the antitumor activity of melatonin on gallbladder cancer was explored both in vitro and in vivo. After treatment with different concentrations of melatonin, the cell viability, migration, and invasion of gallbladder cancer cells (NOZ and GBC-SD cells) were evaluated by CCK-8 assay, wound healing, and Transwell assay.

RESULTS

The results showed that melatonin inhibited growth, migration, and invasion of gallbladder cancer cells. Subsequently, the assays suggested that melatonin significantly induced apoptosis in gallbladder cancer cells and altered the expression of the apoptotic proteins, including Bax, Bcl-2, cytochrome C, cleaved caspase-3, and PARP. Besides, the intracellular reactive oxygen species (ROS) was found to be upregulated after melatonin treatment in gallbladder cancer cells. Melatonin was found to suppress the PI3K/Akt/mTOR signaling pathway in a time-dependent manner by inhibiting the phosphorylation of PI3K, Akt, and mTOR. Treatment with N-acetyl-L-cysteine (NAC) or 740 Y-P remarkably attenuated the antitumor effects of melatonin in NOZ and GBC-SD cells. Finally, melatonin suppressed the growth of GBC-SD cells in an athymic nude mice xenograft model in vivo.

CONCLUSIONS

Our study revealed that melatonin could induce apoptosis by suppressing the PI3K/Akt/mTOR signaling pathway. Therefore, melatonin might serve as a potential therapeutic drug in the future treatment of gallbladder cancer.

Melatonin and its derivative disrupt cancer stem-like phenotypes of lung cancer cells via AKT downregulation

Cancer stem cells (CSCs), a small subpopulation of tumour cells, have properties of self-renewal and multipotency, which drive cancer progression and resistance to current treatments. Compounds potentially targeting CSCs have been recently developed. This study shows how melatonin, an endogenous hormone synthesised by the pineal gland, and its derivative suppress CSC-like phenotypes of human non-small cell lung cancer (NSCLC) cell lines, H460, H23, and A549. The effects of MLT and its derivative, acetyl melatonin (ACT), on CSC-like phenotypes were investigated using assays for anchorage-independent growth, three-dimensional spheroid formation, scratch wound healing ability, and CSC marker and upstream protein signalling expression. Enriched CSC spheroids were used to confirm the effect of both compounds on lung cancer cells. MLT and ACT inhibited CSC-like behaviours by suppression of colony and spheroid formation in NSCLC cell lines. Their effects on spheroid formation were confirmed in CSC-enriched H460 cells. CSC markers, CD133 and ALDH1A1, were depleted by both compounds. The behaviour and factors associated to epithelial-mesenchymal transition, as indicated by cell migration and the protein vimentin, were also decreased by MLT and ACT. Mechanistically, MLT and ACT decreased the expression of stemness proteins Oct-4, Nanog, and β-catenin by reducing active AKT (phosphorylated AKT). Suppression of the AKT pathway was not mediated through melatonin receptors. This study demonstrates a novel role, and its underlying mechanism, for MLT and its derivative ACT in suppression of CSC-like phenotypes in NSCLC cells, indicating that they are potential candidates for lung cancer treatment.

Enhanced anti-angiogenic activity of novel melatonin-like agents

Hypoxia-inducible factor-1 (HIF-1) plays an important role in cellular responses to hypoxia, including the transcriptional activation of several genes involved in tumor angiogenesis. Melatonin, also known as N-acetyl-5-methopxytryptamine, is produced naturally by the pineal gland and has anti-angiogenic effects in cancer through its ability to modulate HIF-1α activity. However, the use of melatonin as a therapeutic is limited by its low oral bioavailability and short half-life. Here, we synthesized melatonin-like molecules with enhanced HIF-1α targeting activity and less toxicity and investigated their effects on tumor growth and angiogenesis, as well as the underlying molecular mechanisms. Among melatonin derivatives, N-butyryl-5-methoxytryptamine (NB-5-MT) showed the most potent HIF-1α targeting activity. This molecule was able to (a) reduce the expression of HIF-1α at the protein level, (b) reduce the transcription of HIF-1α target genes, (c) reduce reactive oxygen species (ROS) generation, (d) decrease angiogenesis in vitro and in vivo, and (e) suppress tumor size and metastasis. In addition, NB-5-MT showed improved anti-angiogenic activity compared with melatonin due to its enhanced cellular uptake. NB-5-MT is thus a promising lead for the future development of anticancer compounds with HIF-1α targeting activity. Given that HIF-1α is overexpressed in the majority of human cancers, the melatonin derivative NB-5-MT could represent a novel potent therapeutic agent for cancer.

Melatonin and neuroblastoma: a novel therapeutic approach

Neuroblastoma is a deadly and serious malignancy among children. Although many developments have been occurred for the treatment of this disease, the rate of mortality is still high. Therefore, it is necessary to search for novel complementary and alternative therapies. Melatonin, a hormone secreted from pineal gland, is a multifunctional agent having anticancer potentials. Recently, several investigations have been conducted indicating melatonin effects against neuroblastoma. In this paper, we summarize current evidence on anti-neuroblastoma effects of melatonin based on cellular pathways.

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.

Modeling Neoplastic Growth in Renal Cell Carcinoma and Polycystic Kidney Disease

Renal cell carcinoma (RCC) and autosomal dominant polycystic kidney disease (ADPKD) share several characteristics, including neoplastic cell growth, kidney cysts, and limited therapeutics. As well, both exhibit impaired vasculature and compensatory VEGF activation of angiogenesis. The PI3K/AKT/mTOR and Ras/Raf/ERK pathways play important roles in regulating cystic and tumor cell proliferation and growth. Both RCC and ADPKD result in hypoxia, where HIF-α signaling is activated in response to oxygen deprivation. Primary cilia and altered cell metabolism may play a role in disease progression. Non-coding RNAs may regulate RCC carcinogenesis and ADPKD through their varied effects. Drosophila exhibits remarkable conservation of the pathways involved in RCC and ADPKD. Here, we review the progress towards understanding disease mechanisms, partially overlapping cellular and molecular dysfunctions in RCC and ADPKD and reflect on the potential for the agile Drosophila genetic model to accelerate discovery science, address unresolved mechanistic aspects of these diseases, and perform rapid pharmacological screens.

An updated review of mechanistic potentials of melatonin against cancer: pivotal roles in angiogenesis, apoptosis, autophagy, endoplasmic reticulum stress and oxidative stress

Cancers are serious life-threatening diseases which annually are responsible for millions of deaths across the world. Despite many developments in therapeutic approaches for affected individuals, the rate of morbidity and mortality is high. The survival rate and life quality of cancer patients is still low. In addition, the poor prognosis of patients and side effects of the present treatments underscores that finding novel and effective complementary and alternative therapies is a critical issue. Melatonin is a powerful anticancer agent and its efficiency has been widely documented up to now. Melatonin applies its anticancer abilities through affecting various mechanisms including angiogenesis, apoptosis, autophagy, endoplasmic reticulum stress and oxidative stress. Regarding the implication of mentioned cellular processes in cancer pathogenesis, we aimed to further evaluate the anticancer effects of melatonin via these mechanisms.

miR-6858 plays a key role in the process of melatonin inhibition of the malignant biological behavior of glioma

MicroRNAs (miRNAs), small non-coding RNA molecules with a length of 18-25 nucleotides, have been shown to be involved in mediating various malignant properties of GBM, including growth, invasion and angiogenesis. Here, we investigated whether miRNAs might be involved in mediating the suppression of malignant properties of GBM by melatonin (MEL), an amine hormone secreted by the pineal gland. Sequencing was performed to screen specifically for miRNAs induced by MEL in U87 and an orthotopically xenografted primary GBM cell line, GBM#P3. MiR-6858-5p was the most significantly up-regulated miR in GBM cell lines in response to MEL (~5 × ). Transfection of a mimic of miR-6858-5p into both cell lines led to a decrease in viability of ~ 50% at 72 h, confirming a suppressive role for miR-6858-5p in GBM. In contrast, an inhibitor of miR-6858-5p rescued GBM cells from MEL suppression of proliferation, migration and invasion. Analysis using Targetscan yielded candidate mRNAs targeted by miR-6858-5p, some of which are involved in the SIRT/AKT signaling pathway. In cells transfected with a mimic or an inhibitor of miR-6858-5p, levels of SIRT3 and downstream components of the AKT signaling pathway were suppressed or up-regulated, respectively, both in vitro and in an in vivo orthotopic xenograft model. Our results elucidated a novel molecular mechanism underlying MEL suppression of GBM, highlighting a role for miRNAs, and provide a potential therapeutic strategy for GBM.

Role and Therapeutic Potential of Melatonin in Various Type of Cancers

Cancer is a large group of diseases and the second leading cause of death worldwide. Lung, prostate, colorectal, stomach, and liver cancers are the most common types of cancer in men, whereas breast, colorectal, lung, cervical, and thyroid cancers are the most common among women. Presently, various treatment strategies, including surgical resection combined with chemotherapy, radiotherapy, nanotherapy, and immunotherapy, have been used as conventional treatments for patients with cancer. However, the clinical outcomes of advanced-stage disease remain relatively unfavorable owing to the emergence of chemoresistance, toxicity, and other undesired detrimental side effects. Therefore, new therapies to overcome these limitations are indispensable. Recently, there has been considerable evidence from experimental and clinical studies suggesting that melatonin can be used to prevent and treat cancer. Studies have confirmed that melatonin mitigates the pathogenesis of cancer by directly affecting carcinogenesis and indirectly disrupting the circadian cycle. Melatonin (MLT) is nontoxic and exhibits a range of beneficial effects against cancer via apoptotic, antiangiogenic, antiproliferative, and metastasis-inhibitory pathways. The combination of melatonin with conventional drugs improves the drug sensitivity of cancers, including solid and liquid tumors. In this manuscript, we will comprehensively review some of the cellular, animal, and human studies from the literature that provide evidence that melatonin has oncostatic and anticancer properties. Further, this comprehensive review compiles the available experimental and clinical data analyzing the history, epidemiology, risk factors, therapeutic effect, clinical significance, of melatonin alone or in combination with chemotherapeutic agents or radiotherapy, as well as the underlying molecular mechanisms of its anticancer effect against lung, breast, prostate, colorectal, skin, liver, cervical, and ovarian cancers. Nonetheless, in the interest of readership clarity and ease of reading, we have discussed the overall mechanism of the anticancer activity of melatonin against different types of cancer. We have ended this report with general conclusions and future perspectives.

The melatonergic pathway and its interactions in modulating respiratory system disorders

Melatonin is a key intracellular neuroimmune-endocrine regulator and coordinator of multiple complex and interrelated biological processes. The main functions of melatonin include the regulation of neuroendocrine and antioxidant system activity, blood pressure, rhythms of the sleep-wake cycle, the retardation of ageing processes, as well as reseting and optimizing mitochondria and thereby the cells of the immune system. Melatonin and its agonists have therefore been mooted as a treatment option across a wide array of medical disorders. This article reviews the role of melatonin in the regulation of respiratory system functions under normal and pathological conditions. Melatonin can normalize the structural and functional organization of damaged lung tissues, by a number of mechanisms, including the regulation of signaling molecules, oxidant status, lipid raft function, optimized mitochondrial function and reseting of the immune response over the circadian rhythm. Consequently, melatonin has potential clinical utility for bronchial asthma, chronic obstructive pulmonary disease, lung cancer, lung vascular diseases, as well as pulmonary and viral infections. The integration of melatonin's effects with the alpha 7 nicotinic receptor and the aryl hydrocarbon receptor in the regulation of mitochondrial function are proposed as a wider framework for understanding the role of melatonin across a wide array of diverse pulmonary disorders.

Effects of melatonin on protecting against lung injury (Review)

Melatonin (MT; N-acetyl-5-methoxy-tryptamine), which has multiple effects and roles, is secreted from the pineal gland at night according to the daily rhythm. In addition to circadian regulation, MT has anti-inflammatory, antioxidant and anticancer functions. Recent studies postulated that MT serves a critical role in apoptosis, anti-ischemic reperfusion injury and anti-proliferative effects on various cells. The current review reported on the underlying mechanism behind the protective effect of MT on lung diseases, such as acute lung injury, acute respiratory distress syndrome, chronic obstructive pulmonary disease, lung ischemia-reperfusion injury, sepsis-induced lung injury and ventilator-induced lung injury. MT is considered an adjuvant with therapeutic drugs for preventing inflammation and is responsible for regulating patient sleep cycles in the intensive care unit. The current review described the anti-inflammatory and antioxidant efficiency of MT with a focus on the molecular mechanisms of action in various lung injuries.

Melatonin and regulation of miRNAs: novel targeted therapy for cancerous and noncancerous disease

miRNAs, small noncoding RNAs with crucial diagnostic and prognostic capabilities, play essential therapeutic roles in different human diseases. These biomarkers are involved in several biological mechanisms and are responsible for the regulation of multiple genes expressions in cells. miRNA-based therapy has shown a very bright future in the case of clinical interventions. Melatonin, the main product of the pineal gland, is a multifunctional neurohormone with numerous therapeutic potentials in human diseases. Melatonin is able to regulate miRNAs in different pathologies such as malignant and nonmalignant diseases, which can be considered as a novel kind of targeted therapy. Herein, this review discusses possible therapeutic utility of melatonin for the regulation of miRNAs in various pathological conditions.

Cyst Reduction by Melatonin in a Novel Drosophila Model of Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) causes progressive cystic degeneration of the renal tubules, the nephrons, eventually severely compromising kidney function. ADPKD is incurable, with half of the patients eventually needing renal replacement. Treatments for ADPKD patients are limited and new effective therapeutics are needed. Melatonin, a central metabolic regulator conserved across all life kingdoms, exhibits oncostatic and oncoprotective activity and no detected toxicity. Here, we used the Bicaudal C (BicC) Drosophila model of polycystic kidney disease to test the cyst-reducing potential of melatonin. Significant cyst reduction was found in the renal (Malpighian) tubules upon melatonin administration and suggest mechanistic sophistication. Similar to vertebrate PKD, the BicC fly PKD model responds to the antiproliferative drugs rapamycin and mimics of the second mitochondria-derived activator of caspases (Smac). Melatonin appears to be a new cyst-reducing molecule with attractive properties as a potential candidate for PKD treatment.

Is Melatonin the Cornucopia of the 21st Century?

Melatonin, an indoleamine hormone produced and secreted at night by pinealocytes and extra-pineal cells, plays an important role in timing circadian rhythms (24-h internal clock) and regulating the sleep/wake cycle in humans. However, in recent years melatonin has gained much attention mainly because of its demonstrated powerful lipophilic antioxidant and free radical scavenging action. Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant. Melatonin-induced signal transduction through melatonin receptors promotes the expression of antioxidant enzymes as well as inflammation-related genes. Melatonin also exerts an immunomodulatory action through the stimulation of high-affinity receptors expressed in immunocompetent cells. Here, we reviewed the efficacy, safety and side effects of melatonin supplementation in treating oxidative stress- and/or inflammation-related disorders, such as obesity, cardiovascular diseases, immune disorders, infectious diseases, cancer, neurodegenerative diseases, as well as osteoporosis and infertility.

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer

BACKGROUND

Sleep disorders have emerged as potential cancer risk factors.

OBJECTIVE

This review discusses the relationships between sleep, obesity, and breathing disorders with concomitant risks of developing cancer.

RESULTS

Sleep disorders result in abnormal expression of clock genes, decreased immunity, and melatonin release disruption. Therefore, these disorders may contribute to cancer development. Moreover, in sleep breathing disorder, which is frequently experienced by obese persons, the sufferer experiences intermittent hypoxia that may stimulate cancer cell proliferation.

DISCUSSION

During short- or long- duration sleep, sleep-wake rhythm disruption may occur. Insomnia and obstructive sleep apnea increase cancer risks. In short sleepers, an increased risk of stomach cancer, esophageal squamous cell cancer, and breast cancer was observed. Among long sleepers (>9 hours), the risk of some hematologic malignancies is elevated.

CONCLUSION

Several factors including insomnia, circadian disruption, obesity, and intermittent hypoxia in obstructive sleep apnea are contributing risk factors for increased risk of several types of cancers. However, further studies are needed to determine the more significant of these risk factors and their interactions.

Melatonin: an endogenous miraculous indolamine, fights against cancer progression

PURPOSE

Melatonin is an amphipathic indolamine molecule ubiquitously present in all organisms ranging from cyanobacteria to humans. The pineal gland is the site of melatonin synthesis and secretion under the influence of the retinohypothalamic tract. Some extrapineal tissues (skin, lens, gastrointestinal tract, testis, ovary, lymphocytes, and astrocytes) also enable to produce melatonin. Physiologically, melatonin regulates various functions like circadian rhythm, sleep-wake cycle, gonadal activity, redox homeostasis, neuroprotection, immune-modulation, and anticancer effects in the body. Inappropriate melatonin secretion advances the aging process, tumorigenesis, visceral adiposity, etc. METHODS: For the preparation of this review, I had reviewed the literature on the multidimensional activities of melatonin from the NCBI website database PubMed, Springer Nature, Science Direct (Elsevier), Wiley Online ResearchGate, and Google Scholar databases to search relevant articles. Specifically, I focused on the roles and mechanisms of action of melatonin in cancer prevention.

RESULTS

The actions of melatonin are primarily mediated by G-protein coupled MT1 and MT2 receptors; however, several intracellular protein and nuclear receptors can modulate the activity. Normal levels of the melatonin protect the cells from adverse effects including carcinogenesis. Therapeutically, melatonin has chronomedicinal value; it also shows a remarkable anticancer property. The oncostatic action of melatonin is multidimensional, associated with the advancement of apoptosis, the arrest of the cell cycle, inhibition of metastasis, and antioxidant activity.

CONCLUSION

The present review has emphasized the mechanism of the anti-neoplastic activity of melatonin that increases the possibilities of the new approaches in cancer therapy.

RAC1 Involves in the Radioresistance by Mediating Epithelial-Mesenchymal Transition in Lung Cancer

Radiation therapy is a common and acceptable approach for lung cancer. Although the benefit of ionizing radiation (IR) is well-established, cancer cells can still survive via pro-survival and metastasis signaling pathways. Ras related C3 botulinum toxin substrate1 (RAC1), a member of Rho family GTPases, plays important roles in cell migration and survival. In the present study, we investigated the effects of RAC1 on the survival of lung cancer cells treated with irradiation. The results showed RAC1 is overexpressed in lung cancer cells and promoted cell proliferation and survival. Furthermore, IR induced RAC1 expression and activity via the activation of PI3K/AKT signaling pathway, and then enhancing cell proliferation, survival, migration and metastasis and increasing levels of epithelial-to-mesenchymal transition (EMT) markers, which facilitated the cell survival and invasive phenotypes. In addition, overexpression of RAC1 attenuated the efficacy of irradiation, while inhibition of RAC1 enhanced sensitivity of irradiation in xenograft tumors in vivo. Collectively, we further found that RAC1 enhanced radioresistance by promoting EMT via targeting the PAK1-LIMK1-Cofilins signaling in lung cancer. Our finding provides the evidences to explore RAC1 as a therapeutic target for radioresistant lung cancer cells.

Melatonin modulates red-ox state and decreases viability of rat pancreatic stellate cells

In this work we have studied the effects of pharmacological concentrations of melatonin (1 µM-1 mM) on pancreatic stellate cells (PSC). Cell viability was analyzed by AlamarBlue test. Production of reactive oxygen species (ROS) was monitored following CM-H₂DCFDA and MitoSOX Red-derived fluorescence. Total protein carbonyls and lipid peroxidation were analyzed by HPLC and spectrophotometric methods respectively. Mitochondrial membrane potential (ψ_m) was monitored by TMRM-derived fluorescence. Reduced (GSH) and oxidized (GSSG) levels of glutathione were determined by fluorescence techniques. Quantitative reverse transcription-polymerase chain reaction was employed to detect the expression of Nrf2-regulated antioxidant enzymes. Determination of SOD activity and total antioxidant capacity (TAC) were carried out by colorimetric methods, whereas expression of SOD was analyzed by Western blotting and RT-qPCR. The results show that melatonin decreased PSC viability in a concentration-dependent manner. Melatonin evoked a concentration-dependent increase in ROS production in the mitochondria and in the cytosol. Oxidation of proteins was detected in the presence of melatonin, whereas lipids oxidation was not observed. Depolarization of ψ_m was noted with 1 mM melatonin. A decrease in the GSH/GSSG ratio was observed, that depended on the concentration of melatonin used. A concentration-dependent increase in the expression of the antioxidant enzymes catalytic subunit of glutamate-cysteine ligase, catalase, NAD(P)H-quinone oxidoreductase 1 and heme oxygenase-1 was detected in cells incubated with melatonin. Finally, decreases in the expression and in the activity of superoxide dismutase were observed. We conclude that pharmacological concentrations melatonin modify the redox state of PSC, which might decrease cellular viability.

Relationship between autophagy, apoptosis and endoplasmic reticulum stress induced by melatonin in osteoblasts by septin7 expression

Melatonin secreted by the pineal body is associated with the occurrence and development of idiopathic scoliosis. Melatonin has a concentration-dependent dual effect on osteoblast proliferation, in which higher concentrations can inhibit osteoblast proliferation and induce apoptosis; however, the underlying mechanism remains unclear. In the present study, flow cytometry was used to demonstrate that osteoblast cells treated with melatonin exhibited significantly increased early and late stage apoptotic rates as the concentration increased. Chromatin condensation in the nucleus and apoptotic body formation could be observed using fluorescent microscopy in osteoblast cells treated with 2 mM melatonin. Western blotting results showed that there was an upregulation in the expression of apoptosis marker proteins [poly (ADP-ribose) polymerase 1 (PARP-1)], endoplasmic reticulum stress [ERS; C/EBP homologous protein (CHOP) and glucose-regulated protein, 78 kDa (GRP78)] and autophagy [microtubule-associated protein 1 light chain 3β (LC3)-I/LC3II]. PARP-1 expression was not altered when treated with ERS inhibitor 4PBA and autophagy inhibitor 3MA, whereas 4PBA or 3MA in combination with 2 mM melatonin (or the three together) significantly increased PARP-1 expression. Furthermore, the use of septin7 small interfering RNA confirmed that increased expression of GRP78 and CHOP was related to septin7, and melatonin- mediated ERS was necessary for septin7 activation. These findings suggest that ERS and autophagy might occur in the early stage of treatment with a high concentration of melatonin, and each might play a protective role in promoting survival; in a later stage, ERS and autophagy might interact and contribute to the induction of apoptosis. Overall, the results indicated that septin7 may be a target protein of melatonin-induced ERS.

Melatonin's Antineoplastic Potential Against Glioblastoma

Glioblastoma (GBM) is one of the most intransigent and aggressive brain tumors, and its treatment is extremely challenging and ineffective. To improve patients’ expectancy and quality of life, new therapeutic approaches were investigated. Melatonin is an endogenous indoleamine with an incredible variety of properties. Due to evidence demonstrating melatonin’s activity against several cancer hallmarks, there is growing interest in its use for preventing and treating cancer. In this review, we report on the potential effects of melatonin, alone or in combination with anticancer drugs, against GBM. We also summarize melatonin targets and/or the intracellular pathways involved. Moreover, we describe melatonin’s epigenetic activity responsible for its antineoplastic effects. To date, there are too few clinical studies (involving a small number of patients) investigating the antineoplastic effects of melatonin against GBM. Nevertheless, these studies described improvement of GBM patients’ quality of life and did not show significant adverse effects. In this review, we also report on studies regarding melatonin-like molecules with the tumor-suppressive properties of melatonin together with implemented pharmacokinetics. Melatonin effects and mechanisms of action against GBM require more research attention due to the unquestionably high potential of this multitasking indoleamine in clinical practice.