Melatonin Analogue Antiproliferative and Cytotoxic Effects on Human Prostate Cancer Cells

Melatonin-Derived Carbon Dots with Free Radical Scavenging Property for Effective Periodontitis Treatment via the Nrf2/HO-1 Pathway

Periodontitis is a chronic inflammatory disease closely associated with reactive oxygen species (ROS) involvement. Eliminating ROS to control the periodontal microenvironment and alleviate the inflammatory response could potentially serve as an efficacious therapy for periodontitis. Melatonin (MT), renowned for its potent antioxidant and anti-inflammatory characteristics, is frequently employed as an ROS scavenger in inflammatory diseases. However, the therapeutic efficacy of MT remains unsatisfactory due to the low water solubility and poor bioavailability. Carbon dots have emerged as a promising and innovative nanomaterial with facile synthesis, environmental friendliness, and low cost. In this study, melatonin-derived carbon dots (MT-CDs) were successfully synthesized via the hydrothermal method. The MT-CDs have good water solubility and biocompatibility and feature excellent ROS-scavenging capacity without additional modification. The in vitro experiments proved that MT-CDs efficiently regulated intracellular ROS, which maintained mitochondrial homeostasis and suppressed the production of inflammatory mediators. Furthermore, findings from the mouse model of periodontitis indicated that MT-CDs significantly inhibited the deterioration of alveolar bone and reduced osteoclast activation and inflammation, thereby contributing to the regeneration of damaged tissue. In terms of the mechanism, MT-CDs may scavenge ROS, thereby preventing cellular damage and the production of inflammatory factors by regulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. The findings will offer a vital understanding of the advancement of secure and effective ROS-scavenging platforms for more biomedical applications.

Melatonin in cancer biology: pathways, derivatives, and the promise of targeted delivery

Melatonin, historically recognized for its primary role in regulating circadian rhythms, has expanded its influence particularly due to its wide range of biological activities. It has firmly established itself in cancer research. To highlight its versatility, we delved into how melatonin interacts with key signaling pathways, such as the Wnt/β-Catenin, PI3K, and NF-κB pathways, which play foundational roles in tumor development and progression. Notably, melatonin can intricately modulate these pathways, potentially affecting various cellular functions such as apoptosis, metastasis, and immunity. Additionally, a comprehensive review of current clinical studies provides a dual perspective. These studies confirm melatonin's potential in cancer management but also underscore its inherent limitations, particularly its limited bioavailability, which often relegates it to a supplementary role in treatments. Despite this limitation, there is an ongoing quest for innovative solutions and current advancements include the development of melatonin derivatives and cutting-edge delivery systems. By synthesizing the past, present, and future, this review provides a detailed overview of melatonin's evolving role in oncology, positioning it as a potential cornerstone in future cancer therapeutics.

Circadian Rhythm Disruption as a Contributor to Racial Disparities in Prostate Cancer

In the United States, African American (AA) men have a 2.4 times higher mortality rate due to prostate cancer than White men. The multifactorial causes of the racial disparities in prostate cancer involve various social determinants of health, socioeconomic status, and access to healthcare. However, emerging evidence also suggests that circadian rhythm disruption (CRD) contributes to prostate cancer, and AA men may be more susceptible to developing CRDs. Circadian rhythms play a significant role in metabolism, hormone secretion, and sleep/wake cycles. Disruption in these circadian rhythms can be caused by airplane travel/jetlag, night shift work, exposure to light, and neighborhood noise levels, which can contribute to sleep disorders and chronic conditions such as obesity, diabetes, cardiovascular disease, and depression. The drivers of the racial disparities in CRD include night shift work, racial discrimination, elevated stress, and residing in poor neighborhoods characterized by high noise pollution. Given the increased vulnerability of AA men to CRDs, and the role that CRDs play in prostate cancer, elucidating the clock-related prostate cancer pathways and their behavior and environmental covariates may be critical to better understanding and reducing the racial disparities in prostate cancer.

Melatonin-A New Prospect in Prostate and Breast Cancer Management

Cancer is a known cause of mortality globally. The management of cancer has been influenced periodically by diverse scientific research for early detection to promote remission and improve quality of life. One of these advancements is the prospect of melatonin (n-acetyl-5-methoxytryptamine) in managing prostate and breast cancers. Melatonin exerts its oncostatic effect by inhibiting angiogenesis, preventing cancer spread and growth, and improving the sensitivity of cancer cells to radiation and chemotherapy in both prostate and breast cancer. This review aims to highlight some of the current studies on melatonin's effect on prostate and breast cancers. We reviewed articles and two randomized controlled trials (RCT) that highlighted the mechanism of melatonin in combating tumorigenesis of these cancers. Articles and RCT studies were obtained by searching PubMed using regular and Medical Subject Heading (MeSH) keyword search strategy. The majority of the articles reviewed supported the use of melatonin in cancer management since inhibition of angiogenesis, cancer proliferation, invasion of normal cells by tumor cells, and improvement in chemotherapeutic and radiation therapy were achieved with its use. In addition, melatonin was also protective against prostate and breast cancers in the general population. Despite the benefits of melatonin in cancer management, most of the studies done were in vivo and in vitro studies, and more studies in human subjects are encouraged to confirm the positive therapeutic use of melatonin.

Melatonin-Loaded Nanocarriers: New Horizons for Therapeutic Applications

The use of nanosized particles has emerged to facilitate selective applications in medicine. Drug-delivery systems represent novel opportunities to provide stricter, focused, and fine-tuned therapy, enhancing the therapeutic efficacy of chemical agents at the molecular level while reducing their toxic effects. Melatonin (N-acetyl-5-methoxytriptamine) is a small indoleamine secreted essentially by the pineal gland during darkness, but also produced by most cells in a non-circadian manner from which it is not released into the blood. Although the therapeutic promise of melatonin is indisputable, aspects regarding optimal dosage, biotransformation and metabolism, route and time of administration, and targeted therapy remain to be examined for proper treatment results. Recently, prolonged release of melatonin has shown greater efficacy and safety when combined with a nanostructured formulation. This review summarizes the role of melatonin incorporated into different nanocarriers (e.g., lipid-based vesicles, polymeric vesicles, non-ionic surfactant-based vesicles, charge carriers in graphene, electro spun nanofibers, silica-based carriers, metallic and non-metallic nanocomposites) as drug delivery system platforms or multilevel determinations in various in vivo and in vitro experimental conditions. Melatonin incorporated into nanosized materials exhibits superior effectiveness in multiple diseases and pathological processes than does free melatonin; thus, such information has functional significance for clinical intervention.

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.

Phase II trial of SM-88, a cancer metabolism based therapy, in non-metastatic biochemical recurrent prostate cancer

Background Androgen deprivation therapy (ADT) is a standard treatment for high-risk biochemically-recurrent, non-metastatic prostate cancer (BRPC) but is not curative and associated with toxicity. Racemetyrosine (SM-88) is an amino-acid analogue used with methoxsalen, phenytoin, and sirolimus (MPS) to enhance SM-88 activity. Method A phase 1b/2, open-label trial in BRPC and rising PSA. Patients were given daily SM-88 (230 mg BID), methoxsalen (10 mg), phenytoin (50 mg), and sirolimus (0.5 mg)). Outcome measures included changes in PSA, circulating tumor cells (CTCs) and imaging. Results 34 subjects were screened, 23 treated and 21 remained on study for ≥12 weeks. The median PSA was 6.4 ng/ml (range 1.7-80.1); doubling-time 6.2 months (range 1.4-36.6) and baseline testosterone 319.1 ng/ml (range 2.5-913.7). Median duration of therapy was 6.5 months (2.6-14.0). CTCs (median 48.5 cells/4 ml (range 15-268) at baseline) decreased a median of 65.3% in 18 of 19 patients. For patients who achieved an absolute CTC nadir count of <10 cells/4 ml (n = 10), disease control was 100% i.e. no metastases or PSA progression, while on trial (p = 0.005). PSA fell by ≥50% in 4.3% (1 subject). No patients developed metastatic disease while on treatment (metastases free survival =100%). There were no treatment-related adverse events (AEs) and quality of life was unchanged from baseline on the EORTC QLQ-C30 and QLQ-PR25. Testosterone levels rose slightly on SM-88 and were unrelated to efficacy or toxicity. Conclusions Use of SM-88 was associated with disease control while maintaining QOL. SM-88 may delay the need for ADT and the associated hormonal side effects. Larger trials are planned.Trial registration number, date of registration - NCT02796898, June 13, 2016.

Melatonin and urological cancers: a new therapeutic approach

Urological cancers are responsible for thousands of cancer-related deaths around the world. Despite all developments in therapeutic approaches for cancer therapy, the absence of efficient treatments is a critical and vital problematic issue for physicians and researchers. Furthermore, routine medical therapies contribute to several undesirable adverse events for patients, reducing life quality and survival time. Therefore, many attempts are needed to explore potent alternative or complementary treatments for great outcomes. Melatonin has multiple beneficial potential effects, including anticancer properties. Melatonin in combination with chemoradiation therapy or even alone could suppress urological cancers through affecting essential cellular pathways. This review discusses current evidence reporting the beneficial effect of melatonin in urological malignancies, including prostate cancer, bladder cancer, and renal cancer.

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.

Serum and Saliva Concentrations of Biochemical Parameters in Men with Prostate Cancer and Benign Prostate Hyperplasia

OBJECTIVES

To find suitable biomarkers for diagnosis of prostate cancer (PC) in serum and saliva; also, to evaluate the diagnostic efficacy of saliva in patients with PC.

METHODS

This case-control study included 20 patients with PC and 20 patients with benign prostatic hyperplasia (BPH). Blood and saliva were collected from the participants and centrifuged. Serum and supernatant saliva were used for biochemical analysis. We evaluated serum and salivary levels of urea, creatinine, prostate-specific antigen (PSA), creatine kinase BB (CK-BB), zinc, β-2 microglobulin (B2M), and melatonin. Also, we used Mann-Whitney U testing, Spearman correlation coefficients, and receiver operating characteristic (ROC) analysis to evaluate the data.

RESULTS

Serum and salivary concentrations of urea, creatinine, PSA, CK-BB, zinc, and B2M were significantly higher in patients with PC, compared with the BPH group (P <.05). However, serum and salivary concentrations of melatonin were significantly lower in patients with PC, compared with BPH group (P <.05). In both groups, salivary concentrations of all markers were lower (P <.05), compared with those values in serum. We observed positive correlation between serum and salivary concentrations of all markers studied (P <.05).

CONCLUSION

From the data, we conclude that investigation using saliva specimens is a noninvasive, simple, and effective tool for screening of biochemical parameters.

Synthesis of a New Water-Soluble Melatonin Derivative with Low Toxicity and a Strong Effect on Sleep Aid

A new melatonin sulfonate derivative sodium 4-(3-(2-acetamidoethyl)-5-methoxy-1H-indol-1-yl) butane-1-sulfonate (MLTBS) with higher water solubility (695 times) and lower cytotoxicity than natural melatonin (MLT) was synthesized, yet with the same sleep aid function. The poor solubility of MLT in water has been improved with a simple chemical reaction, which solves the poor solubility of melatonin in water, overcoming the safety problem caused by adding organic reagents such as dimethyl sulfoxide (DMSO) and ethanol to increase the solubility. Moreover, the modified MLT still has the same sleep aid effect as the natural MLT and higher biological safety. As a novel potential drug for sleep aid, the new MLT derivative could also flourish the application and research of this molecule in medicine and biology.

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.

Free Fatty Acids Promote the Development of Prostate Cancer by Upregulating Peroxisome Proliferator-Activated Receptor Gamma

Introduction

As one of the most common forms of cancer that threatens men's health, prostate cancer (PCa) is under a trend of increasing morbidity and mortality in most countries. More and more studies have pointed out that obesity is closely linked to the occurrence and development of PCa, although there are still many undiscovered molecular mechanisms between the two.

Methods

In the present study, we compare serum lipid levels in patients with PCa and normal individuals. PCa cells (PC3 and 22RV1) were cultured in vitro, the TC/TG/HDL/GLU assay kit was used to detect the glucose and lipid metabolism level of PCa cells, the flow cytometry technique was used to detect the proliferation ability of PCa cells, and the Transwell was used to detect the invasion and migration ability of PCa cells. Western blot/quantitative real-time PCR was used to detect peroxisome proliferator-activated receptor γ (PPARγ) and vimentin/vascular endothelial growth factor-A (VEGF-A) expression levels, and immunohistochemistry was used to observe tumor-associated gene expression levels in nude mice. All data were analysed using the Independent samples t-test or rank sum test.

Results

We found higher levels of FFA in the serum of patients with PCa. In vitro experiments have demonstrated that high levels of FFA can promote the proliferation, migration and invasion of two PCa cells (PC3 and 22RV1) and affect the energy metabolism of PCa cells. The upregulated PPARγ plays a key role in this process, and vimentin may be involved in this signaling pathway.

Conclusion

We infer that high levels of FFA may promote PCa development by upregulating PPARγ expression.

Design, synthesis and biological evaluation of tryptamine salicylic acid derivatives as potential antitumor agents

A series of tryptamine salicylic acid derivatives were synthesized and their antiproliferative activity against MGC-803, MCF-7, HepG2, A549 and HeLa cell lines was evaluated. The structure-activity relationship (SAR) study revealed that different substitutions of the C5 and C3'-C5' positions have certain effects on the anti-proliferation activity. The growth assay revealed that N-[2-(5-bromo-1H-indol-3-yl)-ethyl]-2-hydroxy-3-methyl-benzamide (E20) showed the most potent and broad-spectrum anticancer inhibition of all the cell lines evaluated, and was only more potent than 5-Fu for the gastric cancer cell line. Preliminary studies indicated that compound E20 could inhibit colony formation and migration of MGC-803 cells. The flow cytometry (FCM) results showed that compound E20 arrested the cell cycle in the G2/M phase and induced apoptosis of MGC-803 cells in a concentration-dependent manner. In addition, the western blot results showed that E20 can down-regulate the expression of hexokinase 2. Our studies suggest that the framework of N-[2-(5-bromo-1H-indol-3-yl)-ethyl]-2-hydroxy-3-methyl-benzamide may be consider as a new type of chemical for designing effective anti-cancer drugs targeting gastric cancer cells.

Mitochondrial functions and melatonin: a tour of the reproductive cancers

Cancers of the reproductive organs have a strong association with mitochondrial defects, and a deeper understanding of the role of this organelle in preneoplastic-neoplastic changes is important to determine the appropriate therapeutic intervention. Mitochondria are involved in events during cancer development, including metabolic and oxidative status, acquisition of metastatic potential, resistance to chemotherapy, apoptosis, and others. Because of their origin from melatonin-producing bacteria, mitochondria are speculated to produce melatonin and its derivatives at high levels; in addition, exogenously administered melatonin accumulates in the mitochondria against a concentration gradient. Melatonin is transported into tumor cell by GLUT/SLC2A and/or by the PEPT1/2 transporters, and plays beneficial roles in mitochondrial homeostasis, such as influencing oxidative phosphorylation and electron flux, ATP synthesis, bioenergetics, calcium influx, and mitochondrial permeability transition pore. Moreover, melatonin promotes mitochondrial homeostasis by regulating nuclear DNA and mtDNA transcriptional activities. This review focuses on the main functions of melatonin on mitochondrial processes, and reviews from a mechanistic standpoint, how mitochondrial crosstalk evolved in ovarian, endometrial, cervical, breast, and prostate cancers relative to melatonin's known actions. We put emphasis on signaling pathways whereby melatonin interferes within cancer-cell mitochondria after its administration. Depending on subtype and intratumor metabolic heterogeneity, melatonin seems to be helpful in promoting apoptosis, anti-proliferation, pro-oxidation, metabolic shifting, inhibiting neovasculogenesis and controlling inflammation, and restoration of chemosensitivity. This results in attenuation of development, progression, and metastatic potential of reproductive cancers, in addition to lowering the risk of recurrence and improving the life quality of patients.

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.