Melatonin reduces endothelin-1 expression and secretion in colon cancer cells through the inactivation of FoxO-1 and NF-κβ

Mechanism of Action of Melatonin as a Potential Adjuvant Therapy in Inflammatory Bowel Disease and Colorectal Cancer

Inflammatory bowel disease (IBD), a continuum of chronic inflammatory diseases, is tightly associated with immune system dysregulation and dysbiosis, leading to inflammation in the gastrointestinal tract (GIT) and multiple extraintestinal manifestations. The pathogenesis of IBD is not completely elucidated. However, it is associated with an increased risk of colorectal cancer (CRC), which is one of the most common gastrointestinal malignancies. In both IBD and CRC, a complex interplay occurs between the immune system and gut microbiota (GM), leading to the alteration in GM composition. Melatonin, a neuroendocrine hormone, was found to be involved with this interplay, especially since it is present in high amounts in the gut, leading to some protective effects. Actually, melatonin enhances the integrity of the intestinal mucosal barrier, regulates the immune response, alleviates inflammation, and attenuates oxidative stress. Thereby, the authors summarize the multifactorial interaction of melatonin with IBD and with CRC, focusing on new findings related to the mechanisms of action of this hormone, in addition to its documented positive outcomes on the treatment of these two pathologies and possible future perspectives to use melatonin as an adjuvant therapy.

Tryptophan metabolism in digestive system tumors: unraveling the pathways and implications

Tryptophan (Trp) metabolism plays a crucial role in influencing the development of digestive system tumors. Dysregulation of Trp and its metabolites has been identified in various digestive system cancers, including esophageal, gastric, liver, colorectal, and pancreatic cancers. Aberrantly expressed Trp metabolites are associated with diverse clinical features in digestive system tumors. Moreover, the levels of these metabolites can serve as prognostic indicators and predictors of recurrence risk in patients with digestive system tumors. Trp metabolites exert their influence on tumor growth and metastasis through multiple mechanisms, including immune evasion, angiogenesis promotion, and drug resistance enhancement. Suppressing the expression of key enzymes in Trp metabolism can reduce the accumulation of these metabolites, effectively impacting their role in the promotion of tumor progression and metastasis. Strategies targeting Trp metabolism through specific enzyme inhibitors or tailored drugs exhibit considerable promise in enhancing therapeutic outcomes for digestive system tumors. In addition, integrating these approaches with immunotherapy holds the potential to further enhance treatment efficacy.

The potential therapeutic effect of melatonin in oxaliplatin combination therapy against chemoresistant colorectal cancer cells

BACKGROUND

Oxaliplatin is one of the main therapeutics in colorectal cancer (CRC) chemotherapy. However, in light of multidrug resistance (MDR) phenotype development, the efficacy of oxaliplatin has decreased. This study aimed to assess the potential therapeutic effect of melatonin in oxaliplatin combination therapy for drug-resistant colorectal cancer cells.

METHODS AND RESULTS

Initially, the oxaliplatin-resistant cell line was created of LS174T (LS174T/DR) by using the oxaliplatin IC50 concentration and resting cycles. MTT assays and flow cytometry were applied for assessing cell viability and apoptotic cells. The mRNA expression level of Bax, Bcl2, MT1, MT2, and ABCB1 as well as protein levels of ABCB1, Bcl2, BAX were measured by the qRT-PCR and western blot techniques respectively. P-gp activity was assessed by Rho123 staining. The IC50 concentration of oxaliplatin in resistant cells was increased from 500.7 ± 0.2 nM to 7119 ± 0.1 nM. Bcl2, MT1, MT2, and ABCB1 mRNA plus protein expression levels of Bcl2 and ABCB1 were significantly reduced in resistant cells, along with a marked increase in Bax mRNA and protein levels compared to parental cells. Rho 123 staining revealed a marked reduction in P-gp activities in the combination-treated group compared to the oxaliplatin-treated group.

CONCLUSIONS

The results of cytotoxicity assays, MTT, and flow cytometry revealed that the combination of melatonin and oxaliplatin exerts synergistic effects on induction of oxaliplatin's cytotoxicity in CRC. Our research suggests that combining the treatments of melatonin and oxaliplatin may be considered as a new approach to overcoming oxaliplatin resistance in CRC patients.

The role of tryptophan derivatives as anti-kinetoplastid agents

Kinetoplastids are the causative agents for a spectrum of vector-borne diseases including Leishmaniasis, Chagas disease and Trypanosomiasis that affect millions of people worldwide. In the absence of safe and effective vaccines, chemotherapy, in conjunction with vector control, remain the most significant control approach for kinetoplastid diseases. However, commercially available treatment for these neglected tropical diseases frequently ends up with toxic side effects and increasing resistance. To meet the rising need for innovative medications, alternative chemotherapeutic agents are required. Moreover, insights into target-based mode of action of chemotherapeutic agents are required if novel drugs that may outwit resistance to commercially available drugs are to be developed. Tryptophan has been implicated in a variety of diseases and disorders due to its fundamental role as a precursor to several bioactive metabolites, as well as its importance in the improvement of health and nutrition, diagnostics, and therapeutics. The regulation of tryptophan metabolism plays a fundamental role in the growth of kinetoplastids. Moreover, the levels of tryptophan may serve as a biomarker to distinguish between the stages of kinetoplastids making it an important amino acid to explore for drug targets. The main aim of this review is thus to provide a comprehensive literature synthesis of tryptophan derivatives to explore as potential anti-kinetoplastids. Here we highlight the role of tryptophan derivatives as chemotherapeutic agents against kinetoplastids. The reviewed compounds provide insights into potential new drug interventions that may combat the increasing problem of anti-kinetoplastid resistance.

Efficacy, mechanism, and safety of melatonin-loaded on thermosensitive nanogels for rabbit VX2 tumor embolization: A novel design

Transarterial chemoembolization (TACE) has been widely used for hepatocellular carcinoma. Reducing hypoxia in the tumor microenvironment after TACE remains a challenge as tumor progression is common in post-TACE patients due to the hypoxic tumor microenvironment. In this study, melatonin loaded on p(N-isopropyl-acrylamide-co-butyl methylacrylate) (PIB-M) was used for tumor embolism. Two types of human hepatoma cell lines were used to explore the mechanism by which melatonin prevents the growth and metastasis of cancer cells in vitro. A VX2 rabbit tumor model was used to evaluate the efficacy, mechanism, and safety of PIB-M in vivo. We found that under hypoxic condition, melatonin could inhibit tumor cell proliferation and migration by targeting hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGF-A) in vitro. In vivo, PIB-M inhibited tumor growth and metastasis in rabbit VX2 tumors by promoting apoptosis of tumor cells and targeting related angiogenic proteins and vascular permeability proteins. A high concentration of melatonin in the PIB-M group could be maintained in tumor tissue for 72 h after embolization. The liver and kidney functions were most damaged on the first day but recovered to normal on the seventh day after embolization in the PIB-M group. This novel method may open avenues for reduction of tumor growth and metastasis after TACE and is efficacy and safety, which may be used for treatment for other solid tumors and clinical translation.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

Melatonin as mitochondria-targeted drug

Oxidative damage is associated to numerous diseases as well as aging development. Mitochondria found in most eukaryotic organisms to create the energy of the cell, generate free radicals during its action and they are chief targets of the oxidants. Mitochondrial activities outspread outside the borders of the cell and effect human physiology by modulating interactions among cells and tissues. Therefore, it has been implicated in several human disorders and conditions. Melatonin (MLT) is an endogenously created indole derivative that modifies several tasks, involving mitochondria-associated activities. These possessions make MLT a powerful defender against a selection of free radical-linked disorders. MLT lessens mitochondrial anomalies causing from extreme oxidative stress and may improve mitochondrial physiology. It is a potent and inducible antioxidant for mitochondria. MLT is produced in mitochondria of conceivably of all cells and it also appears to be a mitochondria directed antioxidant which has related defensive properties as the synthesized antioxidant molecules. This chapter summarizes the suggestion that MLT is produced in mitochondria as well as disorders of mitochondrial MLT production that may associate to a number of mitochondria-linked diseases. MLT as a mitochondria-targeted drug is also discussed.

Agomelatine, a Melatonin-Derived Drug, as a New Strategy for the Treatment of Colorectal Cancer

The potential use of agomelatine as an alternative treatment for colorectal cancer is evaluated in this work. The effect of agomelatine was studied in an in vitro model using two cell lines with different p53 statuses (HCT-116, wild-type p53, and HCT-116 p53 null) and an in vivo xenograft model. The inhibitory effects of agomelatine and melatonin were stronger in the cells harboring the wild-type p53, although in both cell lines, the effect of agomelatine was greater than that of the melatonin. In vivo, only agomelatine was able to reduce the volumes of tumors generated by the HCT-116-p53-null cells. Both treatments induced changes in the rhythmicity of the circadian-clock genes in vitro, albeit with some differences. Agomelatine and melatonin regulated the rhythmicity of Per1-3, Cry1, Sirt1, and Prx1 in the HCT-116 cells. In these cells, agomelatine also regulated Bmal1 and Nr1d2, while melatonin changed the rhythmicity of Clock. In the HCT-116-p53-null cells, agomelatine regulated Per1-3, Cry1, Clock, Nr1d2, Sirt1, and Prx1; however, melatonin only induced changes in Clock, Bmal1, and Sirt1. The differences found in the regulation of the clock genes may explain the greater oncostatic effect of agomelatine in CRC.

Epstein-Barr Virus Regulates Endothelin-1 Expression through the ERK/FOXO1 Pathway in EBV-Associated Gastric Cancer

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is one of the four subtypes of gastric carcinoma and its unique clinicopathological mechanism is unclear. Herein, the expression of endothelin-1 (ET-1) in EBVaGC was lower than of Epstein-Barr virus-negative gastric carcinoma (EBVnGC) and associated with a low frequency of lymph node metastasis of EBVaGC. Functional studies showed that the activation of ET-1/endothelin receptor type A (ETAR) axis could promote cell growth, migration, and antiapoptosis. The expression of the ET-1 gene was unrelated to methylation of its promoter region and miRNAs (-1, -125a, -125b). After being treated with MEK1/2 inhibitor (PD0325901), the inactivation of ERK1/2 pathway resulted in downregulation of ET-1 and forkhead box O1 (FOXO1) expression. Further, FOXO1 knockdown decreased the ET-1 expression. These findings indicated that ET-1 could be involved in development of gastric cancer and EBV could suppress the expression of ET-1 via the regulation of the transcription factor FOXO1 through the MAPK/ERK pathway. IMPORTANCE The relationship between Epstein-Barr virus and gastric cancer has been relatively clear. However, there are still many unresolved mechanisms of the virus in tumorigenesis. In recent years, activation of the endothelin-1 signaling axis has been found to play an important role in tumorigenesis, which is involved in tumor angiogenesis and epithelial-mesenchymal transition. EBV genes. In our study, we found that ET-1 was low-expressed in EBV-positive gastric cancer cells, which was due to the inhibition of ERK signaling by EBNA1 through the repression of FOXO1 expression. The low expression of ET-1 limits the proliferation, migration, and anti-apoptotic ability of tumor cells. These findings contribute to further understanding of the role of EBV in EBV-associated gastric cancer.

Melatonin and 5-fluorouracil combination chemotherapy: opportunities and efficacy in cancer therapy

Combined chemotherapy is a treatment method based on the simultaneous use of two or more therapeutic agents; it is frequently necessary to produce a more effective treatment for cancer patients. Such combined treatments often improve the outcomes over that of the monotherapy approach, as the drugs synergistically target critical cell signaling pathways or work independently at different oncostatic sites. A better prognosis has been reported in patients treated with combination therapy than in patients treated with single drug chemotherapy. In recent decades, 5-fluorouracil (5-FU) has become one of the most widely used chemotherapy agents in cancer treatment. This medication, which is soluble in water, is used as the first line of anti-neoplastic agent in the treatment of several cancer types including breast, head and neck, stomach and colon cancer. Within the last three decades, many studies have investigated melatonin as an anti-cancer agent; this molecule exhibits various functions in controlling the behavior of cancer cells, such as inhibiting cell growth, inducing apoptosis, and inhibiting invasion. The aim of this review is to comprehensively evaluate the role of melatonin as a complementary agent with 5-FU-based chemotherapy for cancers. Additionally, we identify the potential common signaling pathways by which melatonin and 5-FU interact to enhance the efficacy of the combined therapy. Video abstract.

Metabolic reprogramming in colorectal cancer: regulatory networks and therapy

With high prevalence and mortality, together with metabolic reprogramming, colorectal cancer is a leading cause of cancer-related death. Metabolic reprogramming gives tumors the capacity for long-term cell proliferation, making it a distinguishing feature of cancer. Energy and intermediate metabolites produced by metabolic reprogramming fuel the rapid growth of cancer cells. Aberrant metabolic enzyme-mediated tumor metabolism is regulated at multiple levels. Notably, tumor metabolism is affected by nutrient levels, cell interactions, and transcriptional and posttranscriptional regulation. Understanding the crosstalk between metabolic enzymes and colorectal carcinogenesis factors is particularly important to advance research for targeted cancer therapy strategies via the investigation into the aberrant regulation of metabolic pathways. Hence, the abnormal roles and regulation of metabolic enzymes in recent years are reviewed in this paper, which provides an overview of targeted inhibitors for targeting metabolic enzymes in colorectal cancer that have been identified through tumor research or clinical trials.

Epidemiological, Clinical, and Genomic Profile in Head and Neck Cancer Patients and Their Families

Inherited cancer predisposition genes are described as risk factors in head and neck cancer (HNC) families. To explore the clinical and epidemiological data and their association with a family history of cancer, we recruited 74 patients and 164 relatives affected by cancer. The germline copy number alterations were evaluated in 18 patients using array comparative genomic hybridization. Two or more first-degree relatives with HNC, tobacco-associated tumor sites (lung, esophagus, and pancreas), or other related tumors (breast, colon, kidney, bladder, cervix, stomach carcinomas, and melanoma) were reported in 74 families. Ten index patients had no exposure to any known risk factors. Family members presented tumors of 19 topographies (30 head and neck, 26 breast, 21 colon). In first-degree relatives, siblings were frequently affected by cancer (n = 58, 13 had HNC). Breast cancer (n = 21), HNC (n = 19), and uterine carcinoma (n = 15) were commonly found in first-degree relatives and HNC in second-degree relatives (n = 11). Nineteen germline genomic imbalances were detected in 13 patients; three presented gains of WRD genes. The number of HNC patients, the degree of kinship, and the tumor types detected in each relative support the role of heredity in these families. Germline alterations may potentially contribute to cancer development.

ARHGEF2/EDN1 pathway participates in ER stress-related drug resistance of hepatocellular carcinoma by promoting angiogenesis and malignant proliferation

Endoplasmic reticulum (ER) stress is widely involved in the drug resistance of hepatocellular carcinoma (HCC), but the mechanism of ER stress-induced drug resistance involves multiple signaling pathways that cannot be fully explained. Exploring genes associated with ER stress could yield a novel therapeutic target for ER stress-induced drug resistance. By analyzing RNA-sequencing, ATAC-sequencing, and Chip-sequencing data of Tunicamycin (TM)-treated or untreated HCC cells, we found that Rho guanine nucleotide exchange factor 2 (ARHGEF2) is upregulated in HCC cells with ER stress. ARHGEF2 plays an active role in tumor malignant progression. Notwithstanding, no research has been done on the link between ER stress and ARHGEF2. The function of ARHGEF2 as a novel downstream effector of ER stress in the angiogenesis and treatment resistance of HCC was revealed in this work. ARHGEF2 overexpression was linked to malignant development and a poor prognosis in HCC. ER stress stimulates the expression of ARHGEF2 through upregulation of ZNF263. Elevated ARHGEF2 accelerates HCC angiogenesis via the EDN1 pathway, enhances HCC cell proliferation and tumor growth both in vitro and in vivo, and contributes to ER stress-related treatment resistance. HCC cell growth was more inhibited when ARHGEF2 knockdown was paired with targeted medicines. Collectively, we uncovered a previously hidden mechanism where ARHGEF2/EDN1 pathway promotes angiogenesis and participates in ER stress-related drug resistance in HCC.

Oncostatic activities of melatonin: Roles in cell cycle, apoptosis, and autophagy

Melatonin, the major secretory product of the pineal gland, not only regulates circadian rhythms, mood, and sleep but also has actions in neoplastic processes which are being intensively investigated. Melatonin is a promising molecule which considered a differentiating agent in some cancer cells at both physiological and pharmacological concentrations. It can also reduce invasive and metastatic status through receptors MT1 and MT2 cytosolic binding sites, including calmodulin and quinone reductase II enzyme, and nuclear receptors related to orphan members of the superfamily RZR/ROR. Melatonin exerts oncostatic functions in numerous human malignancies. An increasing number of studies report that melatonin reduces the invasiveness of several human cancers such as prostate cancer, breast cancer, liver cancer, oral cancer, lung cancer, ovarian cancer, etc. Moreover, melatonin's oncostatic activities are exerted through different biological processes including antiproliferative actions, stimulation of anti-cancer immunity, modulation of the cell cycle, apoptosis, autophagy, the modulation of oncogene expression, and via antiangiogenic effects. This review focuses on the oncostatic activities of melatonin that targeted cell cycle control, with special attention to its modulatory effects on the key regulators of the cell cycle, apoptosis, and telomerase activity.

Melatonin Inhibits NF-κB/CREB/Runx2 Signaling and Alleviates Aortic Valve Calcification

Calcific aortic valve disease (CAVD) is linked to high mortality. Melatonin inhibits nuclear factor-kappa B (NF-κB)/cyclic AMP response element-binding protein (CREB), contributing to CAVD progression. This study determined the role of melatonin/MT1/MT2 signaling in valvular interstitial cell (VIC) calcification. Western blotting and Alizarin red staining were used to analyze NF-κB/CREB/runt-related transcription factor 2 (Runx2) signaling in porcine VICs treated with an osteogenic (OST) medium without (control) or with melatonin for 5 days. Chromatin immunoprecipitation (ChIP) assay was used to analyze NF-κB's transcription regulation of NF-κB on the Runx2 promoter. OST medium-treated VICs exhibited a greater expression of NF-κB, CREB, and Runx2 than control VICs. Melatonin treatment downregulated the effects of the OST medium and reduced VIC calcification. The MT1/MT2 antagonist (Luzindole) and MT1 receptor neutralized antibody blocked the anticalcification effect of melatonin, but an MT2-specific inhibitor (4-P-PDOT) did not. Besides, the NF-κB inhibitor (SC75741) reduced OST medium-induced VIC calcification to a similar extent to melatonin at 10 nmol/L. The ChIP assay demonstrated that melatonin attenuated OST media increased NF-κB binding activity to the promoter region of Runx2. Activation of the melatonin/MT1-axis significantly reduced VIC calcification by targeting the NF-κB/CREB/Runx2 pathway. Targeting melatonin/MT1 signaling may be a potential therapeutic strategy for CAVD.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

The interplay of pineal hormones and socioeconomic status leading to colorectal cancer disparity

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite increased screening options and state-of-art treatments offered in clinics, racial differences remain in CRC. African Americans (AAs) are disproportionately affected by the disease; the incidence and mortality are higher in AAs than Caucasian Americans (CAs). At the time of diagnosis, AAs more often present with advanced stages and aggressive CRCs, primarily accounting for the racial differences in therapeutic outcomes and mortality. The early incidence of CRC in AAs could be attributed to race-specific gene polymorphisms and lifestyle choices associated with socioeconomic status (SES). Altered melatonin-serotonin signaling, besides the established CRC risk factors (age, diet, obesity, alcoholism, and tobacco use), steered by SES, glucocorticoid, and Vitamin D status in AAs could also account for the early incidence in this racial group. This review focuses on how the lifestyle factors, diet, allelic variants, and altered expression of specific genes could lead to atypical serotonin and melatonin signaling by modulating the synthesis, secretion, and signaling of these pineal hormones in AAs and predisposing them to develop more aggressive CRC earlier than CAs. Crosstalk between gut microbiota and pineal hormones and its impact on CRC pathobiology is addressed from a race-specific perspective. Lastly, the status of melatonin-focused CRC treatments, the need to better understand the perturbed melatonin signaling, and the potential of pineal hormone-directed therapeutic interventions to reduce CRC-associated disparity are discussed.

Therapeutic potential of melatonin in colorectal cancer: Focus on lipid metabolism and gut microbiota

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies. The occurrence and development of CRC are complicated processes. Obesity and dysbacteriosis have been increasingly regarded as the main risk factors for CRC. Understanding the etiology of CRC from multiple perspectives is conducive to screening for some potential drugs or new treatment strategies to limit the serious side effects of conventional treatment and prolong the survival of CRC patients. Melatonin, a natural indoleamine, is mainly produced by the pineal gland, but it is also abundant in other tissues, including the gastrointestinal tract, retina, testes, lymphocytes, and Harder's glands. Melatonin could participate in lipid metabolism by regulating adipogenesis and lipolysis. Additionally, many studies have focused on the potential beneficial effects of melatonin in CRC, such as promotion of apoptosis; inhibition of cell proliferation, migration, and invasion; antioxidant activity; and immune regulation. Meaningfully, gut microbiota is the main determinant of all aspects of health and disease (including obesity and tumorigenesis). The gut microbiota is of great significance for understanding the relationship between obesity and increased risk of CRC. Although the current understanding of how the melatonin-mediated gut microbiota coordinates a variety of physiological and pathological activities is fairly comprehensive, there are still many unknown topics to be explored in the face of a complex nutritional status and a changeable microbiota. This review summarizes the potential links among melatonin, lipid metabolism, gut microbiota, and CRC to promote the development of melatonin as a preventive and therapeutic agent for CRC.

Effects of melatonin and doxorubicin on primary tumor and metastasis in breast cancer model

BACKGROUND

Melatonin exerts oncostatic effects on breast cancer via immunomodulation and anti-oxidation. Doxorubicin is an effective chemotherapeutic agent, but parallel studies also provide ample evidence of an off-target effect of Doxorubicin in breast cancer patients.

OBJECTIVE

Combinatorial use of doxorubicin and melatonin has not been comprehensively analyzed in breast cancer models. We hypothesized that the anti-oxidative, anti-proliferative and anti-inflammatory effects of melatonin could ameliorate the off-target effects of doxorubicin in breast cancer patients and enhance the anti-tumoral effects of doxorubicin. The goal of the study is to test this hypothesis in cancer cell lines and xenografted mice.

METHODS

The effects of Melatonin and doxorubicin on the cell viability were evaluated in 4T1-Brain Metastatic Tumor (4TBM). Furthermore, the effects of melatonin and doxorubicin on the primary tumors and systemic metastasis were evaluated in the xenografted mice. Lung and liver tissues were removed and metastasis analyses were performed. The levels of p65, phospho-STAT3, CD11b+, GR1+, Ki67, and cleaved caspase-3 proteins were determined with immunohistochemistry and western blot analysis. We examined the effects of melatonin and Melatonin+Doxorubicin combination therapy on 4TBM cells.

RESULTS

Our results showed that doxorubicin inhibited the proliferation of metastatic breast cancer cells while melatonin did not affect cells. Tumor growth and metastasis were markedly suppressed in melatonin alone and combination with doxorubicin. The expression of CD11b+ and GR1+ proteins which are indicators of myeloid-derived suppressor cells (MDSCs) were noted to be reduced in both primary tumor and metastatic tissues in melatonin and doxorubicin groups.

CONCLUSION

The combination of melatonin with doxorubicin reduced primary tumor growth and distant metastasis. Based on these results, melatonin is a promising candidate for combinatory use with conventional chemotherapeutics for breast cancer treatment.

Melatonin Enhances Anti-tumoral Effects of Menadione on Colon Cancer Cells

BACKGROUND

Colon cancer is one of the most important causes of death in the entire world. New pharmacological strategies are always needed, especially in resistant variants of this pathology. We have previously reported that drugs such as menadione (MEN), D, L-buthionine-S,R-sulfoximine or calcitriol, used in combination, enhanced cell sensibility of breast and colon tumour models, due to their ability to modify the oxidative status of the cells. Melatonin (MEL), a hormone regulating circadian rhythms, has anti-oxidant and anti-apoptotic properties at low concentrations, while at high doses, it has been shown to inhibit cancer cell growth.

OBJECTIVE

The objective of this study is to determine the antitumoral action of the combination MEN and MEL on colon cancer cells.

METHODS

Caco-2 cells were employed to evaluate the effects of both compounds, used alone or combined, on cellular growth/morphology, oxidative and nitrosative stress, and cell migration.

RESULTS

MEN plus MEL dramatically reduced cell proliferation in a time and dose-dependent manner. The antiproliferative effects began at 48 h. At the same time, the combination modified the content of superoxide anion, induced the formation of reactive nitrogen species and enhanced catalase activity. Cell migration process was delayed. Also, changes in nuclear morphology consistent with cell death were observed.

CONCLUSION

The enhanced effect of simultaneous use of MEN and MEL on Caco-2 cells suggests that this combined action may have therapeutic potential as an adjuvant on intestinal cancer acting in different oncogenic pathways.

Prognostic Significance of Alternative Splicing Genes in Cervical Squamous Cell Carcinoma and Endocervical Adenocarcinoma

Background

Alternative splicing (AS) acts on many tumors and its relationship with cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) needs to be researched.

Methods

RNA sequencing data and clinical information of CESC cohorts were obtained from the Cancer Genome Atlas (TCGA) and SpliceSeq was used to analyze the splicing profile of mRNA in CESC. UpSetR displayed the intersections among AS events and univariate analysis chose survival-associated AS and splicing factor (SF) genes. Functional analysis was operated on Enrichr, STRING database and MCODE analysis were used to evaluate protein-protein interaction (PPI) information. LASSO and multivariate analysis constructed prognostic model and risk analysis of tumor infiltrating immune cells was also conducted.

Results

A total of 402 AS-generated genes were found to be associated with CESC prognosis. Functional analysis showed that Golgi to lysosome transport was enriched. PPI network suggested that UBA52 was most functional. Dendritic cells activated, dendritic cells resting, macrophages M0, mast cells resting, T cells CD4 memory activated and T cells CD8 were most correlative with the risk score.

Conclusion

SFs and AS events can directly or indirectly affect the prognosis of CESC patients and this study identified SNRPA and CELF2 as two CESC-engaged SFs.

Transcriptomic analysis reveals that coxsackievirus B3 Woodruff and GD strains use similar key genes to induce FoxO signaling pathway activation in HeLa cells

Coxsackievirus B3 (CVB3) is a major cause of viral myocarditis in humans. Although there have been studies on CVB3 infection and pathogenesis, the precise disease mechanism is still not clear. In this study, we used RNA-seq technology to compare the transcriptomic profile of virus-infected HeLa cells to that of uninfected cells to identify key genes involved in host-virus interaction. For this, two CVB3 strains, CVB3 Woodruff, an experimental strain, and GD16-69/GD/CHN/2016, a clinical strain, were selected to examine the common mechanisms underlying their infection. Transcriptomic profiles revealed increased expression of the cell cycle genes CCNG2, GADD45B, PIM1, RBM15, KLF10, and RIOK3 and decreased expression of CYBA. The autophagy-related genes ATG12 and YOD1 were found to be upregulated, while the expression of SOD2 and XPO1 increased slightly in infected cells, and only a minor change was observed in GABARAP expression. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed the FoxO signaling pathway to be enriched and showed a close interaction with differentially expressed genes (DEGs) in the protein-protein interaction network. DEGs associated with related pathways such as cell cycle, autophagy, and oxidative stress resistance were also confirmed by qRT-PCR. In summary, the FoxO signaling pathway was activated during infection with both CVB3 strains and was found to have a regulatory role in downstream pathways such as cell cycle, autophagy, oxidative stress resistance, and the antiviral immune response.

Melatonin as a Therapeutic Agent for the Inhibition of Hypoxia-Induced Tumor Progression: A Description of Possible Mechanisms Involved

Hypoxia has an important role in tumor progression via the up-regulation of growth factors and cellular adaptation genes. These changes promote cell survival, proliferation, invasion, metastasis, angiogenesis, and energy metabolism in favor of cancer development. Hypoxia also plays a central role in determining the resistance of tumors to chemotherapy. Hypoxia of the tumor microenvironment provides an opportunity to develop new therapeutic strategies that may selectively induce apoptosis of the hypoxic cancer cells. Melatonin is well known for its role in the regulation of circadian rhythms and seasonal reproduction. Numerous studies have also documented the anti-cancer properties of melatonin, including anti-proliferation, anti-angiogenesis, and apoptosis promotion. In this paper, we hypothesized that melatonin exerts anti-cancer effects by inhibiting hypoxia-induced pathways. Considering this action, co-administration of melatonin in combination with other therapeutic medications might increase the effectiveness of anti-cancer drugs. In this review, we discussed the possible signaling pathways by which melatonin inhibits hypoxia-induced cancer cell survival, invasion, migration, and metabolism, as well as tumor angiogenesis.

Use of Melatonin Is Associated With Lower Risk of Colorectal Cancer in Older Adults

INTRODUCTION

Preclinical evidence suggests that melatonin may affect cellular pathways involved in colorectal cancer (CRC). We sought to test whether melatonin use was associated with decreased risk of CRC using population-based data.

METHODS

We performed a nationwide cohort study using a new-user study design. We identified a total of 58,657 incident melatonin users aged 50 years and older from the Prescribed Drug Register, and matched them with 175,971 comparisons who did not use melatonin, on the ratio of 1:3. The Cox regression model was used to calculate hazard ratios and 95% confidence intervals.

RESULTS

The incidence rate of CRC was 10.40 per 10,000 person-years for melatonin users, whereas the rate was 12.82 per 10,000 person-years in the nonusers. We found a significant negative association between melatonin use and risk of CRC (adjusted hazard ratio, 0.82; 95% confidence interval, 0.72-0.92). A test for trend showed a significant dose-response correlation (P < 0.001). The decrease of CRC risk was independent of tumor location and stage at diagnosis. When stratified by age groups, the inverse association was significant only among individuals aged 60 years and older.

DISCUSSION

This population-based cohort study suggests that the use of melatonin was associated with a reduced risk of CRC. Further studies are needed to confirm the observed association and to explore the underlying mechanisms.

Melatonin as an Adjuvant to Antiangiogenic Cancer Treatments

Melatonin is a hormone with different functions, antitumor actions being one of the most studied. Among its antitumor mechanisms is its ability to inhibit angiogenesis. Melatonin shows antiangiogenic effects in several types of tumors. Combination of melatonin and chemotherapeutic agents have a synergistic effect inhibiting angiogenesis. One of the undesirable effects of chemotherapy is the induction of pro-angiogenic factors, whilst the addition of melatonin is able to overcome these undesirable effects. This protective effect of the pineal hormone against angiogenesis might be one of the mechanisms underlying its anticancer effect, explaining, at least in part, why melatonin administration increases the sensitivity of tumors to the inhibitory effects exerted by ordinary chemotherapeutic agents. Melatonin has the ability to turn cancer totally resistant to chemotherapeutic agents into a more sensitive chemotherapy state. Definitely, melatonin regulates the expression and/or activity of many factors involved in angiogenesis which levels are affected (either positively or negatively) by chemotherapeutic agents. In addition, the pineal hormone has been proposed as a radiosensitizer, increasing the oncostatic effects of radiation on tumor cells. This review serves as a synopsis of the interaction between melatonin and angiogenesis, and we will outline some antiangiogenic mechanisms through which melatonin sensitizes cancer cells to treatments, such as radiotherapy or chemotherapy.

Dietary Melatonin and Glycine Decrease Tumor Growth through Antiangiogenic Activity in Experimental Colorectal Liver Metastasis

Despite multimodal treatment strategies, clinical outcomes of advanced stage colorectal cancer (CRC) patients remain poor. Neoadjuvant/adjuvant chemotherapy efficacy is limited due to chemoresistance, toxicity, and negative side effects. Since both melatonin and glycine have anti-cancer activities without relevant side effects, this study was designed to investigate their combined effects in experimental CRC liver metastases. CRC metastasis with CC531 cells were induced in male Wistar rats. Melatonin and glycine alone or their combination were supplemented for 14 days (n = 100). Blood parameters, a micro-computed tomography scan (tumor volume over time), and immunohistochemistry for Ki67 and CD31 expression in tumor tissue were compared between groups. Melatonin and glycine alone significantly reduced the tumor volume by 63.2% (p = 0.002) and 43% (p = 0.044) over time, respectively, while tumor volume increased by 8.7% in the controls. Moreover, treatment with melatonin and glycine alone reduced the tumor proliferation index. Most interestingly, the combination therapy did not have any influence on the above-mentioned tumor parameters. The leukocyte count was significantly increased with melatonin at the end of the experiment (p = 0.012) which was due to a high lymphocytes count. Tumor microvascular density was significantly reduced in all treatment groups. The results of this study suggest an inhibitory function for melatonin and glycine alone in the case of CRC liver metastasis growth by acting as natural antiangiogenic molecules, followed by angiogenesis-dependent cancer proliferation and immunomodulation.

Molecular targets for the management of gastrointestinal cancer using melatonin, a natural endogenous body hormone

Gastrointestinal cancer is one of the most common cancers globally. Melatonin, a natural endogenous body hormone, has been of interest for years, due to its anti-cancer characteristics, such as antiproliferative, antimetastatic, and cytotoxic as well as apoptotic induction. Through regulating several proteins such as melatonin upregulated mRNAs and proteins of downregulated Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2), as well as cytoplasmic protein such as calcium-binding proteins calmodulin or tubulin, and nuclear receptors, including RORα/RZR, and acts by non-receptor-regulated mechanisms, melatonin can exert anti-cancer efficacy. Moreover, melatonin modulates angiogenesis by targeting mRNA and protein expression of endothelin-converting enzyme (ECE-1) protein. In the present review, we address in vivo, in vitro and clinical reports on its anti-cancer efficacies, and the molecular mechanisms of action responsible for these effects. We advance the possibility of therapeutic melatonin administration for cancer therapy.

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.

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 inhibitory effect of melatonin on human prostate cancer

Prostate cancer (PCa) is one of the most commonly diagnosed human cancers in males. Nearly 191,930 new cases and 33,330 new deaths of PCa are estimated in 2020. Androgen and androgen receptor pathways played essential roles in the pathogenesis of PCa. Androgen depletion therapy is the most used therapies for primary PCa patients. However, due to the high relapse and mortality of PCa, developing novel noninvasive therapies have become the focus of research. Melatonin is an indole-like neurohormone mainly produced in the human pineal gland with a prominent anti-oxidant property. The anti-tumor ability of melatonin has been substantially confirmed and several related articles have also reported the inhibitory effect of melatonin on PCa, while reviews of this inhibitory effect of melatonin on PCa in recent 10 years are absent. Therefore, we systematically discuss the relationship between melatonin disruption and the risk of PCa, the mechanism of how melatonin inhibited PCa, and the synergistic benefits of melatonin and other drugs to summarize current understandings about the function of melatonin in suppressing human prostate cancer. We also raise several unsolved issues that need to be resolved to translate currently non-clinical trials of melatonin for clinic use. We hope this literature review could provide a solid theoretical basis for the future utilization of melatonin in preventing, diagnosing and treating human prostate cancer.

Melatonin and Cancer: A Polyhedral Network Where the Source Matters

Melatonin is one of the most phylogenetically conserved signals in biology. Although its original function was probably related to its antioxidant capacity, this indoleamine has been “adopted” by multicellular organisms as the “darkness signal” when secreted in a circadian manner and is acutely suppressed by light at night by the pineal gland. However, melatonin is also produced by other tissues, which constitute its extrapineal sources. Apart from its undisputed chronobiotic function, melatonin exerts antioxidant, immunomodulatory, pro-apoptotic, antiproliferative, and anti-angiogenic effects, with all these properties making it a powerful antitumor agent. Indeed, this activity has been demonstrated to be mediated by interfering with various cancer hallmarks, and different epidemiological studies have also linked light at night (melatonin suppression) with a higher incidence of different types of cancer. In 2007, the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption, where melatonin plays a central role. Our aim is to review, from a global perspective, the role of melatonin both from pineal and extrapineal origin, as well as their possible interplay, as an intrinsic factor in the incidence, development, and progression of cancer. Particular emphasis will be placed not only on those mechanisms related to melatonin’s antioxidant nature but also on the recently described novel roles of melatonin in microbiota and epigenetic regulation.

Melatonin inhibits proliferation and viability and promotes apoptosis in colorectal cancer cells via upregulation of the microRNA-34a/449a cluster

Colorectal cancer (CRC) has a significant burden on healthcare systems worldwide, and is associated with high morbidity and mortality rates in patients. In 2020, the estimated new cases of colon cancer in the United States are 78,300 in men and 69,650 in women. Thus, developing effective and novel alternative agents and adjuvants with reduced side effects is important to reduce the lethality of the disease and improve the quality of life of patients. Melatonin, a pineal hormone that possesses numerous physiological functions, including anti-inflammatory and antitumor activities, can be found in various tissues, including the gastrointestinal tract. Melatonin exerts anticarcinogenic effects via various mechanisms; however, the identified underlying molecular mechanisms do not explain the full breadth of anti-CRC effects mediated by melatonin. MicroRNAs (miRs) serve critical roles in tumorigenesis, however, whether melatonin can inhibit CRC by regulating miRs is not completely understood. In the present study, the roles and mechanism underlying melatonin in CRC were investigated. The proliferation of human CRC cells was tested by CCK8, EDU and colony formation assay. The apoptosis of cancer cells was detected by flow cytometry and western blotting. A xenograft mouse model was constructed and the proliferation and apoptosis of tumor tissue was detected by Ki-67 and TUNEL staining assay respectively. Reverse transcription-quantitative PCR and western blotting were performed to measure the regulation of miRs on mRNA, and the dual-luciferase report analysis experiment was used to verify the direct target genes of miRs. Compared with the control group, melatonin inhibited viability and proliferation, and induced apoptosis in CRC cells. Additionally, the effect of melatonin in a xenograft mouse model was assessed. Compared with the control group, melatonin significantly enhanced the expression levels of the miR-34a/449a cluster, reduced CRC cell proliferation and viability, and increased CRC cell apoptosis. Finally, the dual-luciferase reporter assay indicated that Bcl-2 and Notch1 were the target mRNAs of the miR-34a/449a cluster. To the best of our knowledge, the present study was the first to suggest that melatonin inhibited proliferation and viability, and promoted apoptosis in CRC cells via upregulating the expression of the miR-34a/449a cluster in vitro and in vivo. Therefore, melatonin may serve as a potential therapeutic for CRC.

The role of melatonin in colorectal cancer treatment: a comprehensive review

Colorectal cancer (CRC) is one of the most common types of cancer worldwide, known as the second leading cause of cancer-related deaths annually. Currently, multimodal treatment strategies, including surgical resection, combined with chemotherapy and radiotherapy, have been used as conventional treatments in patients with CRC. However, clinical outcome of advanced stage disease remains relatively discouraging, due mainly to appearance of CRC chemoresistance, toxicity, and other detrimental side effects. New strategies to overcome these limitations are essential. During the last decades, melatonin (MLT) has been shown to be a potent antiproliferative, anti-metastatic agent with cytotoxic effects on different types of human malignancies, including CRC. Hence, this comprehensive review compiles the available experimental and clinical data analyzing the effects of MLT treatment in CRC patients and its underlying molecular mechanisms.

Daily and seasonal mitochondrial protection: Unraveling common possible mechanisms involving vitamin D and melatonin

From an evolutionary point of view, vitamin D and melatonin appeared very early and share functions related to defense mechanisms. In the current clinical setting, vitamin D is exclusively associated with phosphocalcic metabolism. Meanwhile, melatonin has chronobiological effects and influences the sleep-wake cycle. Scientific evidence, however, has identified new actions of both molecules in different physiological and pathological settings. The biosynthetic pathways of vitamin D and melatonin are inversely related relative to sun exposure. A deficiency of these molecules has been associated with the pathogenesis of cardiovascular diseases, including arterial hypertension, neurodegenerative diseases, sleep disorders, kidney diseases, cancer, psychiatric disorders, bone diseases, metabolic syndrome, and diabetes, among others. During aging, the intake and cutaneous synthesis of vitamin D, as well as the endogenous synthesis of melatonin are remarkably depleted, therefore, producing a state characterized by an increase of oxidative stress, inflammation, and mitochondrial dysfunction. Both molecules are involved in the homeostatic functioning of the mitochondria. Given the presence of specific receptors in the organelle, the antagonism of the renin-angiotensin-aldosterone system (RAAS), the decrease of reactive species of oxygen (ROS), in conjunction with modifications in autophagy and apoptosis, anti-inflammatory properties inter alia, mitochondria emerge as the final common target for melatonin and vitamin D. The primary purpose of this review is to elucidate the common molecular mechanisms by which vitamin D and melatonin might share a synergistic effect in the protection of proper mitochondrial functioning.

Melatonin: An atypical hormone with major functions in the regulation of angiogenesis

Melatonin (N-acetyl-5-methoxytryptamine), a pleotropic molecule with a wide distribution, has received considerable attention in recent years, mostly because of its various major effects on tissues or cells since it has both receptor-dependent and receptor-independent actions over a wide range of concentrations. These biological and physiological functions of melatonin include regulation of circadian rhythms by modulating the expression of core oscillator genes, scavenging the reactive oxygen species and reactive nitrogen species, modulating the immune system and inflammatory response, and exerting cytoprotective and antiapoptotic effects. Given the multiple critical roles of melatonin, dysregulation of its production or any disruption in signaling through its receptors may have contributed in the development of a wide range of disorders including type 2 diabetes, aging, immune-mediated diseases, hypertension, and cancer. Herein, we focus on the modulatory effects of melatonin on angiogenesis and its implications as a therapeutic strategy in cancer and related diseases.

Melatonin Induces Apoptosis and Inhibits the Proliferation of Cancer Cells via Reactive Oxygen Species-mediated MAPK and mTOR Pathways

Background:

Recent human and animal studies have demonstrated the oncostatic properties of N-acetyl-5-methoxytryptamine (melatonin) in different types of cancer. However, in few cancer cell lines including colorectal cancer cell line (HT-29), acute T cell leukemia cell line (JURKAT) and cervical cancer cell line (HeLa), precise oncostatic mechanism induced by melatonin is yet to be described.

Objectives:

The aim of this study is to investigate the effects of melatonin in HT-29, JURKAT and HeLa cells and to determine the underlying molecular mechanism.

Methods:

Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay while cell cycle, apoptosis and membrane potential were analysed by flow cytometry. Reactive oxygen species (ROS) was detected by 2',7'.dichlorofluorescein diacetate(DCFH-DA) staining. Protein expressions were determined by Western blot.

Results:

Our results showed that melatonin suppressed cell proliferation, increased the number of sub G1 hypodiploid cells and cell cycle arrest in HT-29, JURKAT and HeLa cells. Besides, melatonin also induced early and late apoptosis, although there were marked variations in responses between different cell lines (sensitivity; HeLa > HT-29 >JURKAT). Apart from that, staining with DCHF-DA demonstrated ROS production that was induced in a dose-dependent manner in HeLa, HT-29 and JURKAT cells. Moreover, the apoptotic process and oncostatic effect of melatonin were seen to be associated with extracellular-signal-regulated kinase (ERK) and stress-activated protein kinase/c-Jun NH (2)-terminal kinase (SAPK-JNK) signalling cascades in HeLa cells. In HT-29 and JURKAT cells, melatonin induced apoptosis via activation of p38 mitogen-activated protein kinases (p38), ERK and SAPK-JNK signalling pathways. In all three cell lines, the apoptotic event was triggered by the mammalian target of rapamycin (mTOR)-mediated activation of the downstream target rapamycininsensitive companion of mTOR (RICTOR) and/or regulatory-associated protein of mTOR (RAPTOR) proteins.

Conclusions:

Our findings confirm that melatonin induces apoptosis through reactive oxygen speciesmediated dysregulated mitogen-activated protein kinase (MAPK) and mTOR signalling pathways in these cancer cell lines.

EDN1 gene potentially involved in the development of acute mountain sickness

Previous investigations have indicated that environmental and genetic factors collectively contribute to the development of acute mountain sickness (AMS), but whether the EDN1 gene is involved in AMS remains to be elucidated. A total of 356 healthy male soldiers who had not traveled to high altitudes in the previous 12 months were enrolled in our study. All participants were taken by plane from 500 m (Chengdu in Sichuan Province) to a 3700 m highland (Lhasa) within 2 hours. Clinical data were collected within 24 hours, and pulmonary function parameters were completed simultaneously. Genotypes were obtained by using iMLDR genotyping assays. A total of 237 soldiers (66.57%) presented AMS symptoms, including headache, dizziness, gastrointestinal upset and fatigue. Soldiers with AMS showed an increase in heart rate (HR), plasma tryptophan and serotonin, and a decrease in SaO2, FEV1, PEF, FVC, V75, V50, V25 and MMF (all P < 0.01). Notably, allele T in single nucleotide polymorphism (SNP) rs2070699 showed a positive correlation with the occurrence of AMS. A general linear regression analysis showed that rs2060799, Mean Arterial Pressure (MAP), SaO2, FVC, tryptophan and serotonin were independent predictors for the occurrence of AMS. Importantly, the area under the curve (AUC) values for tryptophan (0.998), serotonin (0.912) and FVC (0.86) had diagnostic specificity and sensitivity. Our results demonstrated that AMS is accompanied by changes in lung function parameters, increased plasma tryptophan and serotonin levels, and that the EDN1 polymorphism is a potential risk factor for AMS.

Melatonin reverses nasopharyngeal carcinoma cisplatin chemoresistance by inhibiting the Wnt/β-catenin signaling pathway

Cisplatin (DDP)-based concurrent chemo-radiotherapy is a standard approach to treat locoregionally advanced nasopharyngeal carcinoma (NPC). However, many patients eventually develop recurrence and/or distant metastasis due to chemoresistance. In this study, we aimed to elucidate the effects of melatonin on DDP chemoresistance in NPC cell lines in vitro and vivo, and we explored potential chemoresistance mechanisms. We found that DDP chemoresistance in NPC cells is mediated through the Wnt/β-catenin signaling pathway. Melatonin not only reversed DDP chemoresistance, but also enhanced DDP antitumor activity by suppressing the nuclear translocation of β-catenin, and reducing expression of Wnt/β-catenin response genes in NPC cells. In vivo, combined treatment with DDP and melatonin reduced tumor burden to a greater extent than single drug-treatments in an orthotopic xenograft mouse model. Our findings provide novel evidence that melatonin inhibits the Wnt/β-catenin pathway in NPC, and suggest that melatonin could be applied in combination with DDP to treat NPC.

Melatonin Regulates Cisplatin Resistance and Glucose Metabolism Through Hippo Signaling in Hepatocellular Carcinoma Cells

Introduction and Aim

Hepatocellular carcinoma (HCC) is a primary malignancy that occurs in the liver. Clinical cases have been recorded worldwide, particularly in the Saharan area and Asia. In the present work, we aimed to probe the characteristics of melatonin involved in human HCC development, especially in cisplatin resistance and glucose metabolism.

Methods

Two HCC cells, HepG2 and Hep3B cells, were treated with melatonin. Cell cycle test was then used to define the role of melatonin in cell progression while Western blotting and qPCR assay were applied to determine the associated proteins in the treatment. Annexin V/PI staining and MTT assay was used to probe the involvement of melatonin in cisplatin-induced cell apoptosis process. Successively, we assessed glucose consumption in melatonin treated cells along with Western blotting for detection of GLUT-3 expression level. Yes-associated protein (YAP), a key regulator of Hippo signaling pathway, was further examined to characterize the function of melatonin on adjusting GLUT3 and Bcl-2 expression.

Results

Melatonin enabled inhibition of HepG2 and Hep3B proliferation and cell cycle progression via affecting the cell cycle-associated proteins. Annexin V/PI staining and MTT assay results demonstrated that melatonin assisted cisplatin-induced apoptosis accompanied with upregulated caspase-3 and poly ADP-ribose polymerase (PARP) cleavage, as well as Bcl-2 expression. It revealed that melatonin inhibits glucose uptake and ATP production via downregulation of Glucose transporter 3 (GLUT3). In addition, YAP was downregulated by melatonin treatment. The YAP depletion in HepG2 and Hep3B cells suppressed mRNA and protein expression of Bcl-2 and GLUT3, whereas overexpression of YAP in melatonin treated cells partly reversed the melatonin-induced inhibition on proliferation, cisplatin-induced apoptosis, and GLUT3 and Bcl-2 expression.

Conclusion

Melatonin hindered HCC proliferation and aided cisplatin resistance via regulating the Hippo signaling pathway.

Molecular and Cellular Mechanisms of Melatonin in Osteosarcoma

Osteosarcoma, the most common primary bone malignancy, occurs most frequently in adolescents with a peak of incidence at 11-15 years. Melatonin, an indole amine hormone, shows a wide range of anticancer activities. The decrease in melatonin levels simultaneously concurs with the increase in bone growth and the peak age distribution of osteosarcoma during puberty, so melatonin has been utilized as an adjunct to chemotherapy to improve the quality of life and clinical outcomes. While a large amount of research has been conducted to understand the complex pleiotropic functions and the molecular and cellular actions elicited by melatonin in various types of cancers, a few review reports have focused on osteosarcoma. Herein, we summarized the anti-osteosarcoma effects of melatonin and its underlying molecular mechanisms to illustrate the known significance of melatonin in osteosarcoma and to address cellular signaling pathways of melatonin in vitro and in animal models. Even in the same kind of osteosarcoma, melatonin has been sparingly investigated to counteract tumor growth, apoptosis, and metastasis through different mechanisms, depending on different cell lines. We highlighted the underlying mechanism of anti-osteosarcoma properties evoked by melatonin, including antioxidant activity, anti-proliferation, induction of apoptosis, and the inhibition of invasion and metastasis. Moreover, we discussed the drug synergy effects of the role of melatonin involved and the method to fortify the anti-cancer effects on osteosarcoma. As a potential therapeutic agent, melatonin is safe for children and adolescents and is a promising candidate for an adjuvant by reinforcing the therapeutic effects and abolishing the unwanted consequences of chemotherapies.

The Therapeutic Effect of Melatonin on GC by Inducing Cell Apoptosis and Autophagy Induced by Endoplasmic Reticulum Stress

Background

Gastric cancer (GC) is the main malignancy affecting a large population worldwide. Lack of effective enough treatment is one of the leading factors contributing to the high mortality rate. Melatonin, a naturally occurring compound, has been proven to exert cytotoxic and antiproliferative effects on human gastric cancers. Nevertheless, the mechanisms of anti-gastric cancer of melatonin remain elucidated. It is believed that endoplasmic reticulum (ER) stress and its resultant unfolded protein response (UPR) are connected to the survival, progression, and chemoresistance of various tumor cells via multiple cellular procedures, such as autophagy. In this study, the effects of melatonin on human gastric cancer cell lines AGS and SGC-7901 was assessed to reveal the interaction between melatonin, endoplasmic reticulum stress, and autophagy in gastric cancer.

Methods

CCK-8, the wound healing analysis, colony formation assay, immunofluorescence analysis, Western blotting, flow cytometry, and animal models were used in the current study.

Results

The data demonstrated that melatonin could inhibit GC growth, proliferation, and invasion both in vivo and in vitro. Apoptosis and autophagy induced in a concentration-dependent manner is response to melatonin-induced ER stress. Melatonin induced the expression of apoptotic and autophagy-related proteins, which was markedly attenuated by the ER stress inhibitor 4-PBA and autophagy inhibitor 3-MA. In addition, we used the specific IRE1 inhibitor STF 083010, finding that inhibiting IRE1 could considerably relieve ER stress-induced autophagy activity, as revealed by the reduction of LC3-II and Beclin-1.

Conclusion

This study confirmed that melatonin-induced inhibition of GC cell proliferation is mediated by the activation of the IRE/JNK/Beclin1 signaling.

O-GlcNAcylation of YY1 stimulates tumorigenesis in colorectal cancer cells by targeting SLC22A15 and AANAT

Emerging studies have revealed that O-GlcNAcylation plays pivotal roles in the tumorigenesis of colorectal cancers (CRCs). However, the underlying mechanism still remains largely unknown. Here, we demonstrated that Yin Yang 1 (YY1) was O-GlcNAcylated by O-GlcNAc transferase (OGT) and O-GlcNAcylation of YY1 could increase the protein expression by enhancing its stability. O-GlcNAcylation facilitated transformative phenotypes of CRC cell in a YY1-dependent manner. Also, O-GlcNAcylation stimulates YY1-dependent transcriptional activity. Besides, we also identified the oncoproteins, SLC22A15 and AANAT, which were regulated by YY1 directly, are responsible for the YY1 stimulated tumorigenesis. Furthermore, we identified the main putative O-GlcNAc site of YY1 at Thr236, and mutating of this site decreased the pro-tumorigenic capacities of YY1. We concluded that O-GlcNAcylation of YY1 stimulates tumorigenesis in CRC cells by targeting SLC22A15 and AANAT, suggesting that YY1 O-GlcNAcylation might be a potential effective therapeutic target for treating CRC.

Therapeutic Opportunities in Colorectal Cancer: Focus on Melatonin Antioncogenic Action

Colorectal cancer (CRC) influences individual health worldwide with high morbidity and mortality. Melatonin, which shows multiple physiological functions (e.g., circadian rhythm, immune modulation, and antioncogenic action), can be present in almost all organisms and found in various tissues including gastrointestinal tract. Notably, melatonin disruption is closely associated with the elevation of CRC incidence, indicating that melatonin is effective in suppressing CRC development and progression. Mechanistically, melatonin favors in activating apoptosis and colon cancer immunity, while reducing proliferation, autophagy, metastasis, and angiogenesis, thereby exerting its anticarcinogenic effects. This review highlights that melatonin can be an adjuvant therapy and be beneficial in treating patients suffering from CRC.

The potential therapeutic actions of melatonin in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and lethal disease worldwide. Melatonin, an indoleamine produced in pineal gland, shows anticancer effects on a variety of cancers, especially CRC. After clarifying the pathophysiology of CRC, the association of circadian rhythm with CRC, and the relationship between shift work and the incidence of CRC is reviewed. Next, we review the role of melatonin receptors in CRC and the relationship between inflammation and CRC. Also included is a discussion of the mechanism of gene regulation, control of cell proliferation, apoptosis, autophagy, antiangiogenesis and immunomodulation in CRC by melatonin. A review of the drug synergy of melatonin with other anticancer drugs suggests its usefulness in combination therapy. In summary, the information compiled may serve as comprehensive reference for the various mechanisms of action of melatonin against CRC, and as a guide for the design of future experimental research and for advancing melatonin as a therapeutic agent for CRC.