Melatonin inhibits TPA-induced oral cancer cell migration by suppressing matrix metalloproteinase-9 activation through the histone acetylation

Multifaceted roles of melatonin in oncology: an insight into its therapeutic potential in cancer management

Cancer remains the leading cause of death worldwide. The treatment of cancer has become increasing complex. Current treatment options for cancer include surgical resection, chemotherapy, radiotherapy, nanomedicine, and immunotherapy. Recent experimental and clinical studies have provided substantial evidence supporting the potential use of melatonin as a preventive and therapeutic agent in oncology. Melatonin (N-acetyl-5-methoxy-tryptamine), a pleiotropic and multitasking molecule, is secreted from the pineal gland during the night under normal light-dark conditions. Beyond its role in circadian regulation, melatonin exhibits antioxidant, anti-aging, immunomodulatory, and anti-cancer properties. Melatonin exerts significant apoptotic, angiogenic, oncostatic, and anti-proliferative effects on a variety of cancer cells. This review discusses the influence of melatonin on cancer cells through mechanisms involving cell cycle regulation, stimulation of apoptosis, autophagy induction, epigenetic modification, and transcriptional regulation.

Therapeutic applications of melatonin in disorders related to the gastrointestinal tract and control of appetite

Most animals have large amounts of the special substance melatonin, which is controlled by the light/dark cycle in the suprachiasmatic nucleus. According to what is now understood, the gastrointestinal tract (GIT) and other areas of the body are sites of melatonin production. According to recent studies, the GIT and adjacent organs depend critically on a massive amount of melatonin. Not unexpectedly, melatonin's many biological properties, such as its antioxidant, anti-inflammatory, pro-apoptotic, anti-proliferative, anti-metastasis, and antiangiogenic properties, have drawn the attention of researchers more and more. Because melatonin is an antioxidant, it produces a lot of secretions in the GIT's mucus and saliva, which shields cells from damage and promotes the development of certain GIT-related disorders. Melatonin's ability to alter cellular behavior in the GIT and other associated organs, such as the liver and pancreas, is another way that it functions. This behavior alters the secretory and metabolic activities of these cells. In this review, we attempted to shed fresh light on the many roles that melatonin plays in the various regions of the gastrointestinal tract by focusing on its activities for the first time.

Potential of melatonin to reverse epigenetic aberrations in oral cancer: new findings

It is now an accepted principle that epigenetic alterations cause cellular dyshomeostasis and functional changes, both of which are essential for the initiation and completion of the tumor cycle. Oral carcinogenesis is no exception in this regard, as most of the tumors in the different subsites of the oral cavity arise from the cross-reaction between (epi)genetic inheritance and the huge challenge of environmental stressors. Currently, the biochemical machinery is put at the service of the tumor program, halting the cell cycle, triggering uncontrolled proliferation, driving angiogenesis and resistance to apoptosis, until the archetypes of the tumor phenotype are reached. Melatonin has the ability to dynamically affect the epigenetic code. It has become accepted that melatonin can reverse (epi)genetic aberrations present in oral and other cancers, suggesting the possibility of enhancing the oncostatic capacity of standard multimodal treatments by incorporating this indolamine as an adjuvant. First steps in this direction confirm the potential of melatonin as a countermeasure to mitigate the detrimental side effects of conventional first-line radiochemotherapy. This single effect could produce synergies of extraordinary clinical importance, allowing doses to be increased and treatments not to be interrupted, ultimately improving patients' quality of life and prognosis. Motivated by the urgency of improving the medical management of oral cancer, many authors advocate moving from in vitro and preclinical research, where the bulk of melatonin cancer research is concentrated, to systematic randomized clinical trials on large cohorts. Recognizing the challenge to improve the clinical management of cancer, our motivation is to encourage comprehensive and robust research to reveal the clinical potential of melatonin in oral cancer control. To improve the outcome and quality of life of patients with oral cancer, here we provide the latest evidence of the oncolytic activity that melatonin can achieve by manipulating epigenetic patterns in oronasopharyngeal tissue.

EF-24, a Curcumin Analog, Inhibits Cancer Cell Invasion in Human Nasopharyngeal Carcinoma through Transcriptional Suppression of Matrix Metalloproteinase-9 Gene Expression

Cancer metastasis is a main cause of failure in treating subjects with nasopharyngeal carcinoma (NPC) and is frequently linked to high death rates. EF-24, an analog of curcumin, has exhibited many anti-cancer properties and enhanced bioavailability over curcumin. Nevertheless, the effects of EF-24 on the invasiveness of NPC are poorly understood. In this study, we demonstrated that EF-24 effectively inhibited TPA-induced motility and invasion responses of human NPC cells but elicited very limited cytotoxicity. In addition, the TPA-induced activity and expression of matrix metalloproteinase-9 (MMP-9), a crucial mediator of cancer dissemination, were found to be reduced in EF-24-treated cells. Our reporter assays revealed that such a reduction in MMP-9 expression by EF-24 was transcriptionally mediated by NF-κB via impeding its nuclear translocation. Further chromatin immunoprecipitation assays displayed that the EF-24 treatment decreased the TPA-induced interaction of NF-κB with the MMP-9 promoter in NPC cells. Moreover, EF-24 inhibited the activation of JNK in TPA-treated NPC cells, and the treatment of EF-24 together with a JNK inhibitor showed a synergistic effect on suppressing TPA-induced invasion responses and MMP-9 activities in NPC cells. Taken together, our data demonstrated that EF-24 restrained the invasiveness of NPC cells through the transcriptional suppression of MMP-9 gene expression, implicating the usefulness of curcumin or its analogs in controlling the spread of NPC.

Melatonin: Emerging Player in the Management of Oral Cancer

Oral cancer (OC) has emerged as a major medical and social issue in many industrialized nations due to the high death rate. It is becoming increasingly common in people under the age of 45, although the underlying causes and mechanisms of this increase remain unclear. Melatonin, as a pleiotropic hormone, plays a pivotal role in a wide variety of cellular and physiological functions. Mounting evidence supports melatonin's ability to modify/influence oral carcinogenesis, help in the reduction of the incidence of OC, and increase chemo- and radiosensitivity. Despite its potential anti-carcinogenic effects, the precise function of melatonin in the management of OC is not well understood. This review summarizes the current knowledge regarding melatonin function in anti-carcinogenesis mechanisms for OC. In addition, clinical assessment and the potential therapeutic utility of melatonin in OC are discussed. This review will provide a basis for researchers to create new melatonin-based personalized medicines for treating and preventing OC.

Interactions of melatonin with various signaling pathways: implications for cancer therapy

Melatonin is a neuro-hormone with conserved roles in evolution. Initially synthetized as an antioxidant molecule, it has gained prominence as a key molecule in the regulation of the circadian rhythm. Melatonin exerts its effect by binding to cytoplasmic and intra-nuclear receptors, and is able to regulate the expression of key mediators of different signaling pathways. This ability has led scholars to investigate the role of melatonin in reversing the process of carcinogenesis, a process in which many signaling pathways are involved, and regulating these pathways may be of clinical significance. In this review, the role of melatonin in regulating multiple signaling pathways with important roles in cancer progression is discussed, and evidence regarding the beneficence of targeting malignancies with this approach is presented.

Non-Invasive and Real-Time Monitoring of the Breast Cancer Metastasis Degree via Metabolomics

Breast cancer (BC) is a serious threat to women's health and metastasis is the major cause of BC-associated mortality. Various techniques are currently used to preoperatively describe the metastatic status of tumors, based on which a comprehensive treatment protocol was determined. However, accurately staging a tumor before surgery remains a challenge, which may lead to the miss of optimal treatment options. More severely, the failure to detect and remove occult micrometastases often causes tumor recurrences. There is an urgent need to develop a more precise and non-invasive strategy for the detection of the tumor metastasis in lymph nodes and distant organs. Based on the facts that tumor metastasis is closely related to the primary tumor microenvironment (TME) evolutions and that metabolomics profiling of the circulatory system can precisely reflect subtle changes within TME, we suppose whether metabolomic technology can be used to achieve non-invasive and real-time monitoring of BC metastatic status. In this study, the metastasis status of BC mouse models with different tumor-bearing times was firstly depicted to mimic clinical anatomic TNM staging system. Metabolomic profiling together with metastasis-related changes in TME among tumor-bearing mice with different metastatic status was conducted. A range of differential metabolites reflecting tumor metastatic states were screened and in vivo experiments proved that two main metastasis-driving factors in TME, TGF-β and hypoxia, were closely related to the regular changes of these metabolites. The differential metabolites level changes were also preliminarily confirmed in a limited number of clinical BC samples. Metabolite lysoPC (16:0) was found to be useful for clinical N stage diagnosis and the possible cause of its changes was analyzed by bioinformatics techniques.

Melatonin as an oncostatic agent: Review of the modulation of tumor microenvironment and overcoming multidrug resistance

Multi drug resistance (MDR) generally limits the efficacy of chemotherapy in cancer patients and can be categorized into primary or acquired resistance. Melatonin (MLT), a lipophilic hormone released from pineal gland, is a molecule with oncostatic effects. Here, we will briefly review the contribution of different microenvironmental components including fibroblasts, immune and inflammatory cells, stem cells and vascular endothelial cells in tumor initiation, progression and development. Then, the mechanisms by which MLT can potentially affect these elements and regulate drug resistance will be presented. Finally, we will explain how different studies have used novel strategies incorporating MLT to suppress cancer resistance against therapeutics.

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.

Usefulness of Melatonin and Other Compounds as Antioxidants and Epidrugs in the Treatment of Head and Neck Cancer

Along with genetic mutations, aberrant epigenetic alterations are the initiators of head and neck cancer carcinogenesis. Currently, several drugs are being developed to correct these epigenetic alterations, known as epidrugs. Some compounds with an antioxidant effect have been shown to be effective in preventing these malignant lesions and in minimizing the complications derived from cytotoxic treatment. Furthermore, in vitro and in vivo studies show a promising role in the treatment of head and neck squamous cell carcinoma (HNSCC). This is the case of supplements with DNA methylation inhibitory function (DNMTi), such as epigallocatechin gallate, sulforaphane, and folic acid; histone deacetylase inhibitors (HDACi), such as sodium butyrate and melatonin or histone acetyltransferase inhibitors (HATi), such as curcumin. The objective of this review is to describe the role of some antioxidants and their epigenetic mechanism of action, with special emphasis on melatonin and butyric acid given their organic production, in the prevention and treatment of HNSCC.

A novel melatonin-regulated lncRNA suppresses TPA-induced oral cancer cell motility through replenishing PRUNE2 expression

The inhibitory effect of melatonin on cancer cell dissemination is well established, yet the functional involvement of lncRNAs in melatonin signaling remains poorly understood. In this study, we identified a melatonin-attenuated lncRNA acting as a potential melatonin-regulated oral cancer stimulator (MROS-1). Downregulation of MROS-1 by melatonin suppressed TPA-induced oral cancer migration through replenishing the protein expression of prune homolog 2 (PRUNE2), which functioned as a tumor suppressor in oral cancer. Melatonin-mediated MROS-1/PRUNE2 expression and cell motility in oral cancer were regulated largely through the activation of JAK-STAT pathway. In addition, MROS-1, preferentially localized in the nuclei, promoted oral cancer migration in an epigenetic mechanism in which it modulates PRUNE2 expression by interacting with a member of the DNA methylation machinery, DNA methyltransferase 3A (DNMT3A). Higher methylation levels of PRUNE2 promoter were associated with nodal metastases and inversely correlated with PRUNE2 expression in head and neck cancer. Collectively, these findings suggest that MROS-1, serving as a functional mediator of melatonin signaling, could predispose patients with oral cancer to metastasize and may be implicated as a potential target for antimetastatic therapies.

Effects of melatonin receptor expression on prognosis and survival in oral squamous cell carcinoma patients

Melatonin receptors can inhibit breast and prostate cancers; however, little is known regarding their effects on oral squamous cell carcinoma. In this study, we collected specimens from 81 patients with oral squamous cell carcinoma and analysed clinicopathological data retrospectively. In addition, the expression of the melatonin receptor was analysed immunohistochemically. Survival rates were calculated using the Kaplan-Meier method and log-rank test. Multivariate analysis was performed based on the Cox proportional-hazards model. Further, an in vitro study was performed using YD15 cells. The cells were transfected with siRNA targeting melatonin receptor 1A and 1B for evaluating the malignancy of melatonin receptors by western blotting, trypan blue-exclusion, colony-forming, wound-healing, and invasion assays. Survival decreased as melatonin receptor expression and clinical and pathological tumour-node-metastasis stages increased. A Cox proportional-hazard model showed that melatonin receptor 1A may serve as a significant predictor of the survival rate of patients with oral squamous cell carcinoma [hazard ratio = 1.423, 95% confidence interval (CI) = 1.019-1.988, p = 0.038]. Melatonin receptor 1A and 1B knockdown significantly suppressed proliferation, migration ability, and invasion ability of YD15 cells in vitro. Our findings reveal that inhibiting melatonin receptor expression may suppress oral squamous cell carcinoma development.

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.

Salivary melatonin in oral squamous cell carcinoma patients

Melatonin's role in circadian rhythm is well documented, as are its' anti-oxidant, oncostatic and anti-inflammatory properties. Poor sleep quality has been associated as a potential risk factor for several malignancies, including head and neck cancers. The purpose of this study is to determine salivary melatonin (MLT) levels in oral squamous cell carcinoma (OSCC) patients, compare the salivary MLT levels with those in healthy individuals and compare the salivary and serum levels in OSCC patients. Furthermore, the aim is to investigate the potential relationship between sleep quality and salivary MLT levels in OSCC patients. Unstimulated (UWS) and stimulated (SWS) whole saliva was sampled from patients with T1N0M0 and T2N0M0 OSCC (N = 34) and 33 sex and age matched healthy subjects. Serum samples were taken from 11 OSCC patients. Sleep quality was measured using Pittsburgh Sleep Quality Index (PSQI) questionnaire. Melatonin levels in UWS and SWS were significantly higher in the OSCC group. Sleep quality was significantly lower in patients with OSCC (P = 0.0001). ROC analysis was found to be significant (P < 0.001) in evaluating MLT concentration limit in diagnosing OSCC. The expected relationship between sleep quality and salivary MLT levels in OSCC patients was not observed. Our results suggest salivary MLT as a potential biomarker that might facilitate non-invasive detection of early stage OSCC.

Melatonin in Cancer Treatment: Current Knowledge and Future Opportunities

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

Effect of Locally Delivered Melatonin as an Adjunct to Nonsurgical Therapy on GCF Antioxidant Capacity and MMP-9 in Stage II Periodontitis Patients: A Randomized Controlled Clinical Trial

Objectives

Periodontitis is characterized by inflammatory destruction of periodontal tissue, loss of attachment, and bone resorption. The increase in reactive oxygen species (ROS) is responsible for the oxidative damage occurring in periodontal tissues. Melatonin has important immunomodulatory, anti-inflammatory, and powerful antioxidant functions. The current study was carried out to evaluate the effect of topical melatonin gel as an adjunct to nonsurgical periodontal therapy.

Methods

This split-mouth randomized controlled clinical trial was performed on 24 patients with grade II periodontitis. Two sites in each patient were randomly assigned; test sites were treated by nonsurgical therapy followed by intrapocket application of 5% melatonin gel. Control sites were treated by nonsurgical therapy followed by intrapocket application of placebo gel. Both the melatonin and placebo gel were applied weekly once for four weeks. Assessment of clinical parameters (PD and CAL) was done at baseline and 3 months after therapy. Total antioxidative capacity (TAC) and matrix metalloproteinase-9 (MMP-9) levels in GCF were also evaluated utilizing commercially available enzyme-linked immunosorbent assay kits (ELISA) at baseline and 3 months after therapy.

Results

Treatment with topical melatonin was associated with a reduction in periodontal inflammation reflected as an improvement in the clinical periodontal parameters. Melatonin-treated sites showed a more statistically significant percent reduction in PD and more statistically significant percent gain in CAL than the control site. Additionally, a significant increase in TAC and a significant decrease in MMP-9 levels in GCF were found in melatonin-treated sites in comparison to control sites.

Conclusions

The adjunctive use of topical melatonin gel with nonsurgical periodontal therapy has potent anti-inflammatory and antioxidant activity in the treatment of grade II periodontitis patients.

Resveratrol inhibits ACHN cells via regulation of histone acetylation

Context: The relationship between resveratrol and histone acetylation in renal cell carcinoma (RCC) has not yet been reported.Objective: To explore the functional role of resveratrol in RCC.Materials and methods: Functional experiments were performed to determine proliferatio n of ACHN cells with treatment of resveratrol (0, 7.8125, 15.625, 31.25 and 62.5 μg/mL, for 12, 24 and 48 h of culture) or 0.1 μM SAHA. The enzyme activities of MMP-2/-9 were measured by gelatine zymography and histone acetylation by Western blot.Results: When the cells were treated with 15.625, 31.25 and 62.5 μg/mL resveratrol, ACHN cells viability was 73.2 ± 3.5%, 61.4 ± 3.1%, 50.2 ± 4.7% for 12 h, 62.7 ± 4.5%, 52.4 ± 5.5%, 40.2 ± 3.8% for 24 h, and 60.8 ± 3.7%, 39.4 ± 5.1%, 37.6 ± 2.7% for 48 h, and the wound closure (%) of migration was increased from 0.6 to 0.7, 0.85, 0.9 for 12 h and from 0.23 to 0.3, 0.48, 0.59 for 24 h. The invasion rate was 8.5 ± 0.9%, 7.4 ± 0.3% and 5.8 ± 0.6%, and cell cycle was arrested at G1 from 42.5 ± 2.9% to 55.3 ± 5.7%, 59.8 ± 3.4%, 68.7 ± 4.6%. MMP-2/-9 expression (p < 0.05) was inhibited by resveratrol. The protein levels of histone acetylation (p < 0.01) was increased by resveratrol.Discussion and conclusions: Our results suggest that these effects might be related to a high level of histone acetylation, and resveratrol can be considered as an alternative treatment for RCC.

In utero alcohol exposure exacerbates endothelial protease activity from pial microvessels and impairs GABA interneuron positioning

In utero alcohol exposure can induce severe neurodevelopmental disabilities leading to long-term behavioral deficits. Because alcohol induces brain defects, many studies have focused on nervous cells. However, recent reports have shown that alcohol markedly affects cortical angiogenesis in both animal models and infants with fetal alcohol spectrum disorder (FASD). In addition, the vascular system is known to contribute to controlling gamma-aminobutyric acid (GABA)ergic interneuron migration in the developing neocortex. Thus, alcohol-induced vascular dysfunction may contribute to the neurodevelopmental defects in FASD. The present study aimed at investigating the effects of alcohol on endothelial activity of pial microvessels. Ex vivo experiments on cortical slices from mouse neonates revealed that in endothelial cells from pial microvessels acute alcohol exposure inhibits both glutamate-induced calcium mobilization and activities of matrix metalloproteinase-9 (MMP-9) and tissue plasminogen activator (tPA). The inhibitory effect of alcohol on glutamate-induced MMP-9 activity was abrogated in tPA-knockout and Grin1^flox/VeCad^cre mice suggesting that alcohol interacts through the endothelial NMDAR/tPA/MMP-9 vascular pathway. Contrasting with the effects from acute alcohol exposure, in mouse neonates exposed to alcohol in utero during the last gestational week, glutamate exacerbated both calcium mobilization and endothelial protease activities from pial microvessels. This alcohol-induced vascular dysfunction was associated with strong overexpression of the N-methyl-d-aspartate receptor subunit GluN1 and mispositioning of the Gad67-GFP interneurons that normally populate the superficial cortical layers. By comparing several human control fetuses with a fetus chronically exposed to alcohol revealed that alcohol exposure led to mispositioning of the calretinin-positive interneurons, whose density was decreased in the superficial cortical layers II-III and increased in deepest layers. This study provides the first mechanistic and functional evidence that alcohol impairs glutamate-regulated activity of pial microvessels. Endothelial dysfunction is characterized by altered metalloproteinase activity and interneuron mispositioning, which was also observed in a fetus with fetal alcohol syndrome. These data suggest that alcohol-induced endothelial dysfunction may contribute in ectopic cortical GABAergic interneurons, that has previously been described in infants with FASD.

Melatonin and gastrointestinal cancers: Current evidence based on underlying signaling pathways

Gastrointestinal (GI) cancers, leading causes of cancer-related deaths, have been serious challenging human diseases up to now. Because of high rates of mortality, late-stage diagnosis, metastasis to distant locations, and low effectiveness and adverse events of routine standard therapies, the quality of life and survival time are low in patients with GI cancers. Hence, many efforts need to be done to explore and find novel efficient treatments. Beneficial effects of melatonin have been reported in a wide variety of human diseases. Melatonin has antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. Various studies have showed the regulatory effects of melatonin on apoptotsis, autophagy and angiogenesis; these properties result in the inhibition of invasion, migration, and proliferation of GI cancer cells in vivo and in vitro. Together, this review suggests that melatonin in combination with anticancer agents may improve the efficacy of routine medicine and survival rate of patients with cancer.

Role and Therapeutic Potential of Melatonin in the Central Nervous System and Cancers

Melatonin (MLT) is a powerful chronobiotic hormone that controls a multitude of circadian rhythms at several levels and, in recent times, has garnered considerable attention both from academia and industry. In several studies, MLT has been discussed as a potent neuroprotectant, anti-apoptotic, anti-inflammatory, and antioxidative agent with no serious undesired side effects. These characteristics raise hopes that it could be used in humans for central nervous system (CNS)-related disorders. MLT is mainly secreted in the mammalian pineal gland during the dark phase, and it is associated with circadian rhythms. However, the production of MLT is not only restricted to the pineal gland; it also occurs in the retina, Harderian glands, gut, ovary, testes, bone marrow, and lens. Although most studies are limited to investigating the role of MLT in the CNS and related disorders, we explored a considerable amount of the existing literature. The objectives of this comprehensive review were to evaluate the impact of MLT on the CNS from the published literature, specifically to address the biological functions and potential mechanism of action of MLT in the CNS. We document the effectiveness of MLT in various animal models of brain injury and its curative effects in humans. Furthermore, this review discusses the synthesis, biology, function, and role of MLT in brain damage, and as a neuroprotective, antioxidative, anti-inflammatory, and anticancer agent through a collection of experimental evidence. Finally, it focuses on the effect of MLT on several neurological diseases, particularly CNS-related injuries.

Pineal gland protects against chemically induced oral carcinogenesis and inhibits tumor progression in rats

Clinical investigations suggest that melatonin suppression and circadian dysfunction may be related to cancer development in shift workers. Studies also show that melatonin suppression after pinealectomy increases cancer incidence in preclinical models. However, no study evaluated the influence of pinealectomy on oral cancer development. In the current study, we investigated the effects of pinealectomy on oral squamous cell carcinoma (OSCC) occurrence and progression in rats. Rats submitted to sham surgery were used as control. Pinealectomy promoted an increase of 140% in OSCC occurrence when compared to sham animals. Tumors from pinealectomized rats displayed a higher volume and thickness than the tumors from sham-operated animals. Pinealectomy induced atrophy of the epithelium adjacent to the oral lesions. Pinealectomized rats showed higher mean number of tumor-associated macrophages and eosinophils in the invasive front of OSCC. In addition, nuclear overexpression of ERK1/2 and p53 was also observed in the front of carcinomas from pinealectomized rats. These results reveal that pineal gland plays a protective role against oral carcinogenesis. The melatonin suppression caused by the pinealectomy might contribute to oral cancer development by acting on ERK1/2 and p53 pathways and regulating tumor inflammation.

Antimetastatic Effects of Sesamin on Human Head and Neck Squamous Cell Carcinoma through Regulation of Matrix Metalloproteinase-2

Background: Sesamin is a lignin present in sesame oil from the bark of Zanthoxylum spp. Sesamin reportedly has anticarcinogenic potential and exerts anti-inflammatory effects on several tumors. Hypothesis/Purpose: However, the effect of sesamin on metastatic progression in human head and neck squamous carcinoma (HNSCC) remains unknown in vitro and in vivo; hence, we investigated the effect of sesamin on HNSCC cells in vitro. Methods and Results: Sesamin-treated human oral cancer cell lines FaDu, HSC-3, and Ca9-22 were subjected to a wound-healing assay. Furthermore, Western blotting was performed to assess the effect of sesamin on the expression levels of matrix metalloproteinase (MMP)-2 and proteins of the MAPK signaling pathway, including p-ERK1/2, P-p38, and p-JNK1/2. In addition, we investigated the association between MMP-2 expression and the MAPK pathway in sesamin-treated oral cancer cells. Sesamin inhibited cell migration and invasion in FaDu, Ca9-22, and HSC-3 cells and suppressed MMP-2 at noncytotoxic concentrations (0 to 40 μM). Furthermore, sesamin significantly reduced p38 MAPK and JNK phosphorylation in a dose-dependent manner in FaDu and HSC-3 cells. Conclusions: These results indicate that sesamin suppresses the migration and invasion of HNSCC cells by regulating MMP-2 and is thus a potential antimetastatic agent for treating HNSCC.

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.

Carbonic Anhydrase III Promotes Cell Migration and Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma

Epithelial–mesenchymal transition (EMT) is strongly correlated with tumor metastasis and contains several protein markers, such as E-cadherin. Carbonic anhydrase III (CA III) exhibits low carbon dioxide hydratase activity in cancer. However, the detailed mechanisms of CA III and their roles in oral cancer are still unknown. This study established a CA III-overexpressed stable clone and observed the expression of CA III protein in human SCC-9 and SAS oral cancer cell lines. The migration and invasion abilities were determined using a Boyden chamber assay. Our results showed that the overexpression of CA III protein significantly increased the migration and invasion abilities in oral cancer cells. Moreover, a whole genome array analysis revealed that CA III regulated epithelial–mesenchymal transition by reducing the expression of epithelial markers. Data from the GEO database also demonstrated that CA III mRNA is negatively correlated with CDH1 mRNA. Mechanistically, CA III increased the cell motility of oral cancer cells through the FAK/Src signaling pathway. In conclusion, this suggests that CA III promotes EMT and cell migration and is potentially related to the FAK/Src signaling pathway in oral cancer.

Effects of miR-34b/miR-892a Upregulation and Inhibition of ABCB1/ABCB4 on Melatonin-Induced Apoptosis in VCR-Resistant Oral Cancer Cells

Multidrug resistance (MDR) is the resistance of cells toward various drugs commonly used in tumor treatment. The mechanism of drug resistance in oral cancer is not completely understood. Melatonin is an endogenously produced molecule involved in active biological mechanisms including antiproliferation, oncogene expression modulation, antitumor invasion and migration, and anti-inflammatory, antioxidant, and antiangiogenic effects. Despite these functions, the effects of melatonin on vincristine (VCR)-resistant human oral cancer cells remain largely unknown. This study analyzed the role of melatonin in VCR-resistant human oral cancer cells along with the underlying mechanism. We determined that melatonin induced the apoptosis and autophagy of VCR-resistant oral cancer cells; these actions were mediated by AKT, p38, and c-Jun N-terminal kinase (JNK). Melatonin inhibited ATP-binding cassette B1 (ABCB1) and ABCB4 expression in vitro and in vivo. Melatonin reduced the drug resistance and promoted the apoptosis of VCR-resistant oral cancer cells through the upregulation of microRNA-892a (miR-892a) and miR-34b-5p expressions. The expression of miR-892a and miR-34b-5p was related to melatonin-induced apoptosis, but not autophagy. Therefore, melatonin is a potential novel chemotherapeutic agent for VCR-resistant human oral cancer cell lines.

Serum melatonin is inversely associated with matrix metalloproteinase-9 in oral squamous cell carcinoma

Matrix-metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) expression levels have been demonstrated to have prognostic value in oral squamous cell carcinoma (OSCC). The present study hypothesized that melatonin, a small lipophilic molecule primarily secreted by the pineal gland, may be able to regulate MMP activity in OSCC progression. This study aimed to investigate the associations between melatonin, MMPs, TIMPs and the histopathological characteristics of patients with OSCC. A total of 40 men with OSCC (mean age, 57±7 years) and 30 healthy men (mean age, 56±5 years) were enrolled in the present study. Enzyme immunoassays were used to measure the serum levels of melatonin, MMP-9, MMP-2, TIMP-1 and TIMP-2 before and after transoral surgery for OSCC. Serum melatonin level was significantly lower in patients with OSCC compared with controls, both pre-surgery and 2 days after surgery (P<0.001). In addition, melatonin level was negatively correlated with MMP-9 (r=-0.6371) and the MMP-9/TIMP-1 ratio (r=-0.4700), but not with the MMP-2 or MMP-2/TIMP-2 ratio, in patients with OSCC. These results demonstrated that low levels of melatonin and high levels of MMP-9 correlated with large tumors with invasive depth (r=-0.35 and r=0.33) and lymph node metastasis (r=-0.56 and r=0.34). The results of this retrospective clinical study suggested that melatonin may be considered as a predictive biomarker of tumor growth and metastasis and a potential therapeutic agent for patients with OSCC.

Insights on Melatonin as an Active Pharmacological Molecule in Cancer Prevention: What's New?

Along with playing an important role in circadian rhythm, melatonin is thought to play a significant role in preventing cells from damage, as well as in the inhibition of growth and in triggering apoptosis in malignant cells. Its relationship with circadian rhythms, energetic homeostasis, diet, and metabolism, is fundamental to achieve a better comprehension of how melatonin has been considered a chemopreventive molecule, though very few papers dealing with this issue. In this article, we tried to review the most recent evidence regarding the protective as well as the antitumoral mechanisms of melatonin, as related to diet and metabolic balance. From different studies, it was evident that an intracellular antioxidant defense mechanism is activated by upregulating an antioxidant gene battery in the presence of high-dose melatonin in malignant cells. Like other broad-spectrum antioxidant molecules, melatonin plays a vital role in killing tumor cells, preventing metastasis, and simultaneously keeping normal cells protected from oxidative stress and other types of tissue damage.

Clinical significance of serum melatonin in predicting the severity of oral squamous cell carcinoma

Melatonin, the primary hormone produced by the pineal gland, is intensely assessed for its anticancer properties. This study aimed to reveal the clinical significance of serum melatonin levels in predicting the severity of oral squamous cell carcinoma (OSCC). For this purpose, 40 male patients with OSCC and 30 healthy subjects were enrolled in this study. The serum levels of melatonin were determined by ELISA. The results revealed that the melatonin concentrations were significantly lower in the patients with OSCC compared with the controls (18.2 vs. 47.6 pg/ml, P<0.001). In addition, the serum melatonin levels had a high predictive accuracy for discriminating patients with OSCC with T-depth of invasion (DOI) II from the healthy controls (89.1%), as well as in discriminating patients with OSCC with nodal metastasis from those without nodal metastasis (83.8%). On the whole, the findings of this study suggest that the serum melatonin concentrations are closely related to the severity of OSCC and may thus be used to assess the different stages of oral cancer objectively and accurately. The present study also supports the conclusion that melatonin may be a potential therapeutic agent for use in the treatment of patients with OSCC.

Potential of Melatonin as Adjuvant Therapy of Oral Cancer in the Era of Epigenomics

The wide variety of epigenetic controls available is rapidly expanding the knowledge of molecular biology even overflowing it. At the same time, it can illuminate unsuspected ways of understanding the etiology of cancer. New emerging therapeutic horizons, then, promise to overcome the current antitumor strategies need. The translational utility of this complexity is particularly welcome in oral cancer (OC), in which natural history is alarmingly disappointing due to the invasive and mutilating surgery, the high relapsing rate, the poor quality of life and the reduced survival after diagnosis. Melatonin activates protective receptor-dependent and receptor-independent processes that prevent tissue cancerisation and inhibit progressive tumor malignancy and metastasis. Related evidence has shown that melatonin pleiotropy encompasses gene expression regulation through all the three best-characterized epigenetic mechanisms: DNA methylation, chromatin modification, and non-coding RNA. OC has received less attention than other cancers despite prognosis is usually negative and there are no significant therapy improvements recorded in the past decade. However, a large research effort is being carried out to elucidate how melatonin´s machinery can prevent epigenetic insults that lead to cancer. In the light of recent findings, a comprehensive examination of biochemistry through which melatonin may reverse epigenetic aberrations in OC is an extraordinary opportunity to take a step forward in the clinical management of patients.

The potential utility of melatonin in the treatment of childhood cancer

Childhood cancer management has improved considerably, with the overall objective of preventing early-life cancers completely. However, cancer remains a major cause of death in children, with the survivors developing anticancer treatment-specific health problems. Therefore, the anticancer treatment needs further improvement. Melatonin is a effective antioxidant and circadian pacemaker. Through multiple mechanisms, melatonin has significant positive effects on multitude adult cancers by increasing survival and treatment response rates, and slowing disease progression. In addition, melatonin appears to be safe for children. As an appealing therapeutic agent, we herein address several key concerns regarding melatonin's potential for treating children with cancer.

Tetrandrine inhibits human brain glioblastoma multiforme GBM 8401 cancer cell migration and invasion in vitro

Tetrandrine (TET) has been reported to induce anti-cancer activity in many human cancer cells and also to inhibit cancer cell migration and invasion. However, there are no reports to show TET inhibits cell migration and invasion in human brain glioblastoma multiforme GBM 8401 cells. In this study, we investigated the anti-metastasis effects of TET on GBM 8401 cells in vitro. Under sub-lethal concentrations (from 1, 5 up to 10 μM), TET significantly inhibited cell mobility, migration and invasion of GBM 8401 cells that were assayed by wound healing and Transwell assays. Gelatin zymography assay showed that TET inhibited MMP-2 activity in GBM 8401 cells. Western blotting results indicated that TET inhibited several key metastasis-related proteins, such as p-EGFR_(Tyr1068) , SOS-1, GRB2, Ras, p-AKT_(Ser473) and p-AKT_(Thr308) , NF-κB-p65, Snail, E-cadherin, N-cadherin, NF-κB, MMP-2 and MMP-9 that were significant reduction at 24 and 48 hours treatment by TET. TET reduced MAPK signaling associated proteins such as p-JNK1/2 and p-c-Jun in GBM 8401 cells. The electrophoretic mobility shift (EMSA) assay was used to investigate NF-κB and DNA binding was reduced by TET in a dose-dependently. Based on these findings, we suggested that TET could be used in anti-metastasis of human brain glioblastoma multiforme GBM 8401 cells in the future.

Antimetastatic effects of Terminalia catappa leaf extracts on cervical cancer through the inhibition of matrix metalloprotein-9 and MAPK pathway

The effects of Terminalia catappa leaf extracts (TCE) have been widely investigated, including its antioxidative, anti-inflammatory, and antidiabetic activity, as well as its antimetastatic effects on several types of human cancer. However, no study has examined the antimetastatic potential of TCE in cervical cancer cells. This study aimed to elucidate the potential antimetastatic properties of ethanol extracts of Terminalia catappa in 12-O-tetradecanoylphorbol-13-acetate treated human cervical cancer cells and investigate the signaling pathway of this process. We demonstrated that TCE elicited very low cytotoxicity and significantly inhibited cellular migration and invasion in human HeLa and SiHa cervical cancer cells. Moreover, the gelatin zymography, reverse transcription-polymerase chain reaction (RT-PCR), and real-time PCR analysis revealed that the activity and mRNA level of matrix metalloproteinase-9 (MMP-9) were inhibited by TCE in a concentration-dependent manner. The Western blot results demonstrated that the highest concentration of TCE (100 μg/ml) reduced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) by 46% in the HeLa cell lines. In conclusion, it was revealed that TCE exerted antimetastatic effects on cervical cancer cells by inhibiting the expression of MMP-9 through the ERK1/2 pathway.

Melatonin May Increase Anticancer Potential of Pleiotropic Drugs

Melatonin (N-acetyl-5-methoxytryptamine) is not only a pineal hormone, but also an ubiquitary molecule present in plants and part of our diet. Numerous preclinical and some clinical reports pointed to its multiple beneficial effects including oncostatic properties, and as such, it has become one of the most aspiring goals in cancer prevention/therapy. A link between cancer and inflammation and/or metabolic disorders has been well established and the therapy of these conditions with so-called pleiotropic drugs, which include non-steroidal anti-inflammatory drugs, statins and peroral antidiabetics, modulates a cancer risk too. Adjuvant therapy with melatonin may improve the oncostatic potential of these drugs. Results from preclinical studies are limited though support this hypothesis, which, however, remains to be verified by further research.

Alterations of 63 hub genes during lingual carcinogenesis in C57BL/6J mice

To identify potential biomarkers of lingual cancer, 75 female C57BL/6J mice were subjected to 16-week oral delivery of 4-nitroquinoline-1-oxide (4NQO; 50 mg/L), with 10 mice used as controls. Lingual mucosa samples representative of normal tissue (week 0) and early (week 12) and advanced (week 28) tumorigenesis were harvested for microarray and methylated DNA immunoprecipitation sequencing (MeDIP-Seq). Combined analysis with Short Time-series Expression Miner (STEM), the Cytoscape plugin cytoHubba, and screening of differentially expressed genes enabled identification of 63 hub genes predominantly altered in the early stage rather than the advanced stage. Validation of microarray results was carried out using qRT-PCR. Of 63 human orthologous genes, 35 correlated with human oral squamous cell carcinoma. KEGG analysis showed "pathways in cancer", involving 13 hub genes, as the leading KEGG term. Significant alterations in promoter methylation were confirmed at Tbp, Smad1, Smad4, Pdpk1, Camk2, Atxn3, and Cdh2. HDAC2, TBP, and EP300 scored ≥10 on Maximal Clique Centrality (MCC) in STEM profile 11 and were overexpressed in human tongue cancer samples. However, expression did not correlate with smoking status, tumor differentiation, or overall survival. These results highlight potentially useful candidate biomarkers for lingual cancer prevention, diagnosis, and treatment.

Mechanisms Underlying Tumor Suppressive Properties of Melatonin

There is considerable evidence that melatonin may be of use in the prevention and treatment of cancer. This manuscript will review some of the human, animal and cellular studies that provide evidence that melatonin has oncostatic properties. Confirmation that melatonin mitigates pathogenesis of cancer will be described from both direct study of its effects on carcinogenesis, and from indirect findings implicating disruption of the circadian cycle. A distinction is made between the role of melatonin in preventing the initiation of the tumorigenic pathway and the ability of melatonin to retard the progression of cancer. Melatonin appears to slow down the rate of advancement of established tumors and there is evidence that it constitutes a valuable complement to standard pharmacological and radiation treatment modalities. There are instances of the beneficial outcomes in cancer treatment which utilize a range of hormones and vitamins, melatonin being among the constituents of the mix. While these complex blends are empirically promising, they are only briefly mentioned here in view of the confounding influence of a multiplicity of agents studied simultaneously. The last section of this review examines the molecular mechanisms that potentially underlie the oncostatic effects of melatonin. Alterations in gene expression following activation of various transcription factors, are likely to be an important mediating event. These changes in gene activity not only relate to cancer but also to the aging process which underlies the onset of most tumors. In addition, epigenetic events such as modulation of histone acetylation and DNA methylation patterns throughout the lifespan of organisms need to be considered. The antioxidant and immunoregulatory roles of melatonin may also contribute to its cancer modulatory properties. Naturally, these mechanisms overlap and interact extensively. Nevertheless, in the interest of clarity and ease of reading, each is discussed as a separate topic section. The report ends with some general conclusions concerning the clinical value of melatonin which has been rather overlooked and understudied.

Melatonin for the prevention and treatment of cancer

The epidemiological studies have indicated a possible oncostatic property of melatonin on different types of tumors. Besides, experimental studies have documented that melatonin could exert growth inhibition on some human tumor cells in vitro and in animal models. The underlying mechanisms include antioxidant activity, modulation of melatonin receptors MT1 and MT2, stimulation of apoptosis, regulation of pro-survival signaling and tumor metabolism, inhibition on angiogenesis, metastasis, and induction of epigenetic alteration. Melatonin could also be utilized as adjuvant of cancer therapies, through reinforcing the therapeutic effects and reducing the side effects of chemotherapies or radiation. Melatonin could be an excellent candidate for the prevention and treatment of several cancers, such as breast cancer, prostate cancer, gastric cancer and colorectal cancer. This review summarized the anticancer efficacy of melatonin, based on the results of epidemiological,experimental and clinical studies, and special attention was paid to the mechanisms of action.

Melatonin inhibits osteosarcoma stem cells by suppressing SOX9-mediated signaling

AIMS

Melatonin (N-acetyl-5-methoxytryptamine) has been reported to suppress epithelial-mesenchymal transition and cancer stem cells in some types of cancer. However, the effects of melatonin on the osteosarcoma stem cells, epithelial-mesenchymal transition and metastasis of osteosarcoma are still not clear. The present study was conducted to dissect the activity of melatonin on the osteosarcoma stem cells and the underlying mechanisms.

MAIN METHODS

MTT, wound healing, transwell assay and western blotting were conducted to determine the effect of melatonin on osteosarcoma cell invasion and migration and downregulation of SOX9-mediated signaling. Tumor spheroid assay and FACS analysis were performed to analyze the inhibition of the osteosarcoma stem cells. In vivo model for tumor formation and metastasis from single cell clone was used to evaluate the suppression of osteosarcoma stem cells by melatonin.

KEY FINDINGS

We demonstrated that melatonin potently suppresses the migration and invasion of osteosarcoma cells. Furthermore, melatonin significantly inhibits the sarcosphere formation of osteosarcoma stem cells and regulates EMT markers of osteosarcoma cells. In vivo mice model showed that melatonin significantly inhibits the initiation and metastasis of osteosarcoma. SOX9 is the key transcription factor mediating the effect of melatonin. Melatonin inhibited of cancer stem cell by down-regulation of SOX9-mediated signaling pathway in osteosarcoma.

SIGNIFICANCE

Collectively, these results deepen the understanding of the biological functions of melatonin and provide new insights for the intervention of osteosarcoma stem cells.

MMP-11 promoted the oral cancer migration and Fak/Src activation

Matrix metalloproteinase-11 (MMP-11) has been observed in most invasive human carcinomas. The current study investigated the association between the clinicopathological characteristics and MMP-11 expression in oral squamous cell carcinoma (OSCC) patients. Immunohistochemistry (IHC) staining was performed to assess MMP-11 expression in 279 patients with OSCC. In addition, the metastatic effects of the MMP-11 overexpression on the OSCC cells were also investigated. We found that MMP-11 expression was present in 118/279 (42.3%) cases and expression of MMP-11 was associated with higher incidence of lymph node metastasis and worse grade of tumor differentiation. Importantly, OSCC patients with strong expression of MMP-11 had a significantly lower survival rate (p=0.010). Furthermore, MMP-11 overexpression in OSCC cells increased in vitro cell migration. Mechanistically, MMP-11 increased the cell motility of OSCC cells through focal adhesion kinase/Src kinase (FAK/Src) pathway. In conclusion, our results revealed that the MMP-11 expression in OSCC samples can predict the progression, especially lymph node metastasis, and the survival of OSCC patients in Taiwan.

Melatonin Inhibits Reactive Oxygen Species-Driven Proliferation, Epithelial-Mesenchymal Transition, and Vasculogenic Mimicry in Oral Cancer

Globally, oral cancer is the most common type of head and neck cancers. Melatonin elicits inhibitory effects on oral cancer; however, the biological function of melatonin and underlying mechanisms remain largely unknown. In this study, we found that melatonin impaired the proliferation and apoptosis resistance of oral cancer cells by inactivating ROS-dependent Akt signaling, involving in downregulation of cyclin D1, PCNA, and Bcl-2 and upregulation of Bax. Melatonin inhibited the migration and invasion of oral cancer cells by repressing ROS-activated Akt signaling, implicating with the reduction of Snail and Vimentin and the enhancement of E-cadherin. Moreover, melatonin hampered vasculogenic mimicry of oral cancer cells through blockage of ROS-activated extracellular-regulated protein kinases (ERKs) and Akt pathways involving the hypoxia-inducible factor 1α. Consistently, melatonin retarded tumorigenesis of oral cancer in vivo. Overall, these findings indicated that melatonin exerts antisurvival, antimotility, and antiangiogenesis effects on oral cancer partly by suppressing ROS-reliant Akt or ERK signaling.

Melatonin exerts anti-oral cancer effect via suppressing LSD1 in patient-derived tumor xenograft models

Aberrant activation of histone lysine-specific demethylase (LSD1) increases tumorigenicity; hence, LSD1 is considered a therapeutic target for various human cancers. Although melatonin, an endogenously produced molecule, may defend against various cancers, the precise mechanism involved in its anti-oral cancer effect remains unclear. Patient-derived tumor xenograft (PDTX) models are preclinical models that can more accurately reflect human tumor biology compared with cell line xenograft models. Here, we evaluated the anticancer activity of melatonin by using LSD1-overexpressing oral cancer PDTX models. By assessing oral squamous cell carcinoma (OSCC) tissue arrays through immunohistochemistry, we examined whether aberrant LSD1 overexpression in OSCC is associated with poor prognosis. We also evaluated the action mechanism of melatonin against OSCC with lymphatic metastases by using the PDTX models. Our results indicated that melatonin, at pharmacological concentrations, significantly suppresses cell proliferation in a dose- and time-dependent manner. The observed suppression of proliferation was accompanied by the melatonin-mediated inhibition of LSD1 in oral cancer PDTXs and oral cancer cell lines. In conclusion, we determined that the beneficial effects of melatonin in reducing oral cancer cell proliferation are associated with reduced LSD1 expression in vivo and in vitro.

Functional genetic variant in the Kozak sequence of WW domain-containing oxidoreductase (WWOX) gene is associated with oral cancer risk

In Taiwan, oral cancer is the fourth leading cancer in males and is associated with exposure to environmental carcinogens. WW domain-containing oxidoreductase (WWOX), a tumor suppressor gene, is associated with the development of various cancers. We hypothesized that genetic variants of WWOX influence the susceptibility to oral cancer. Five polymorphisms of WWOX gene from 761 male patients with oral cancer and 1199 male cancer-free individuals were genotyped. We observed that individuals carrying the polymorphic allele of WWOX rs11545028 are more susceptible to oral cancer. Furthermore, patients with advanced-stage oral cancer were associated with a higher frequency of WWOX rs11545028 polymorphisms with the variant genotype TT than did patients with the wild-type gene. An additional integrated in silico analysis confirmed that rs11545028 affects WWOX expression, which significantly correlates with tumor expression and subsequently with tumor development and aggressiveness. In conclusion, genetic variants of WWOX contribute to the occurrence of oral cancer, and the findings regarding these biomarkers provided a prediction model for risk assessment.

WISP1 genetic variants as predictors of tumor development with urothelial cell carcinoma

OBJECTIVES

Urothelial cell carcinoma (UCC) of the urinary bladder is a major malignancy of the genitourinary tract. Etiological factors, such as the environment, ethnicity, genetics, and diet, contribute to UCC carcinogenesis. WNT1-inducible signaling pathway protein 1 (WISP1), also known as CCN4, a cysteine-rich protein belonging to the Cyr61, CTGF, Nov (CCN) family of matricellular proteins, has many developmental functions and might be involved in carcinogenesis. This study investigated WISP1 single-nucleotide polymorphisms to evaluate UCC susceptibility and clinicopathological characteristics.

MATERIALS AND METHODS

Real-time polymerase chain reaction was used to analyze 4 single-nucleotide polymorphisms of WISP1 in 369 patients with UCC and 738 controls without cancer.

RESULTS

The results showed that in 128 women with UCC who carried WISP1 rs2929973 (AG + GG) variants had a higher risk of developing an advanced muscle-invasive tumor stage (pT2-pT4, P = 0.007) and a large tumor (T1-T4, P = 0.030). Further analyses revealed that a correlation between the expressions of WISP1 and invasive tumor and large tumor size in urothelial carcinoma was observed in the TCGA (The Cancer Genome Atlas) dataset.

CONCLUSIONS

Our results indicated that patients with UCC carrying rs2977530 genetic variants (AG + GG) have a higher risk of developing a more invasive tumor stage and a large tumor. WISP1 polymorphisms may serve as a marker or a therapeutic target in UCC.

Melatonin represses oral squamous cell carcinoma metastasis by inhibiting tumor-associated neutrophils

Tumor-associated neutrophils (TANs) promote metastasis of multiple cancers, including oral squamous cell carcinoma (OSCC). Melatonin (Mel) reportedly exerts anti-metastatic effects on OSCC. However, little is known about the anti-OSCC effects of Mel involved in TANs. In this study, intensive infiltration of TANs was positively associated with advanced stage, lymphatic metastasis, and poor prognosis of OSCC. Moreover, Mel reduced the survival and migration of OSCC-associated neutrophils. Mechanistically, Mel suppressed the TAN release of C-X-C motif chemokine ligand 8, C-C motif chemokine ligand 2 (CCL2), CCL4, and matrix metalloproteinase-9 by blockage of p38 MAPK and Akt signaling. Mel-fostered TANs decreased the migration and invasion of OSCC cells and reduced tube formation in vitro. Additionally, Mel-hampered pro-motility and pro-angiogenesis effects of TANs were dependent on MMP-9 suppression in OSCC. Overall, The beneficial roles of melatonin in retarding OSCC metastasis were implicated with inhibition of TANs.

Fisetin inhibits epidermal growth factor-induced migration of ARPE-19 cells by suppression of AKT activation and Sp1-dependent MMP-9 expression

Purpose

Proliferative vitreoretinopathy (PVR) can result in abnormal migration of RPE cells. Fisetin is a naturally occurring compound that has been reported to have antitumor effects, but its effects on epidermal growth factor (EGF)-induced cell migration and the underlying mechanisms remain unclear.

Methods

Effects of fisetin on EGF-induced cell viability and migration were examined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and in vitro migration assays. Reverse transcription-PCR (RT-PCR) and immunoblotting were performed to evaluate matrix metallopeptidase-9 (MMP-9) expression and activation of specificity protein-1 (Sp1) and protein kinase B (AKT) in ARPE-19 cells treated with EGF and with or without fisetin. Luciferase and chromatin immunoprecipitation (ChIP) assays were performed to examine Sp1 transcription activity and MMP-9 binding activity.

Results

Fisetin did not affect ARPE-19 cell viability and significantly inhibited the EGF-induced migration capacity of ARPE-19 cells. Furthermore, fisetin exerted an antimigratory effect and suppressed MMP-9 mRNA and protein expression. Treatment with EGF induced phosphorylation of AKT and expression of MMP-9 and Sp1. Fisetin combined with LY294002 (an inhibitor of AKT) prevented the EGF-induced migration involved in downregulation of Sp1 and MMP-9 expression. Luciferase and ChIP assays suggested that fisetin remarkably decreased the EGF-induced transcription activity of MMP-9 and Sp1 and inhibited EGF-mediated Sp1 from directly binding to the MMP-9 promoter in ARPE-19 cells.

Conclusions

Fisetin inhibited EGF-induced cell migration via modulation of AKT/Sp1-dependent MMP-9 transcriptional activity. Therefore, fisetin may be a potential agent in the treatment of migratory PVR diseases.

Andrographolide suppresses the migratory ability of human glioblastoma multiforme cells by targeting ERK1/2-mediated matrix metalloproteinase-2 expression

Glioblastoma multiforme (GBM) can be a fatal tumor because of difficulties in treating the related metastasis. Andrographolide is the bioactive component of the Andrographis paniculata. Andrographolide possesses the anti-inflammatory activity and inhibits the growth of various cancers; however, its effect on GBM cancer motility remains largely unknown. In this study, we examined the antimetastatic properties of andrographolide in human GBM cells. Our results revealed that andrographolide inhibited the invasion and migration abilities of GBM8401 and U251 cells. Furthermore, andrographolide inhibited matrix metalloproteinase (MMP)-2 activity and expression. Real-time PCR and promoter activity assays indicated that andrographolide inhibited MMP-2 expression at the transcriptional level. Such inhibitory effects were associated with the suppression of CREB DNA-binding activity and CREB expression. Mechanistically, andrographolide inhibited the cell motility of GBM8401 cells through the extracellular-regulated kinase (ERK) 1/2 pathway, and the blocking of the ERK 1/2 pathway could reverse MMP-2-mediated cell motility. In conclusion, CREB is a crucial target of andrographolide for suppressing MMP-2-mediated cell motility in GBM cells. Therefore, a combination of andrographolide and an ERK inhibitor might be a good strategy for preventing GBM metastasis.