Chemoneuroendocrine therapy of metastatic breast cancer with persistent thrombocytopenia with weekly low-dose epirubicin plus melatonin: a phase II study

Melatonin: Current evidence on protective and therapeutic roles in gynecological diseases

Melatonin, a potent antioxidant and free radical scavenger, has been demonstrated to be effective in gynecological conditions and female reproductive cancers. This review consolidates the accumulating evidence on melatonin's multifaceted protective effects in different pathological contexts. In gynecological conditions such as endometriosis, polycystic ovary syndrome (PCOS), and uterine leiomyoma, melatonin has shown promising effects in reducing oxidative stress, inflammation, and hormonal imbalances. It inhibits adhesion molecules' production, and potentially mitigates leukocyte adherence and inflammatory responses. Melatonin's regulatory effects on hormone production and insulin sensitivity in PCOS individuals make it a promising candidate for improving oocyte quality and menstrual irregularities. Moreover, melatonin exhibits significant antitumor effects by modulating various signaling pathways, promoting apoptosis, and suppressing metastasis in breast cancers and gynecological cancers, including ovarian, endometrial, and cervical cancers. Furthermore, melatonin's protective effects are suggested to be mediated by interactions with its receptors, estrogen receptors and other nuclear receptors. The regulation of clock-related genes and circadian clock systems may also contribute to its inhibitory effects on cancer cell growth. However, more comprehensive research is warranted to fully elucidate the underlying molecular mechanisms and establish melatonin as a potential therapeutic agent for these conditions.

Molecular and cellular mechanisms of melatonin in breast cancer

Breast cancer is considered as one of the most important health problems due to its poor prognosis and high rate of mortality and new diagnosed cases. Annually, a great number of deaths are reported in men and women; this means that despite all the improvements in cancer diagnosis and treatment, still, an intense need for more effective approaches exists. Melatonin is a multivalent compound which has a hand in several cellular and molecular processes and therefore, is an appropriate candidate for treatment of many diseases like cancer. Currently, considerable properties of this agent have oriented the research towards investigating its effects specifically in breast cancer. In this review, we gathered a bunch of evidence in order to give a new sight for breast cancer treatment utilizing melatonin. We expect that in coming years, melatonin will become one of the most common therapeutic drugs with lesser side-effects than other chemotherapeutic drugs.

A New Paradigm in the Relationship between Melatonin and Breast Cancer: Gut Microbiota Identified as a Potential Regulatory Agent

In this review we summarize a possible connection between gut microbiota, melatonin production, and breast cancer. An imbalance in gut bacterial population composition (dysbiosis), or changes in the production of melatonin (circadian disruption) alters estrogen levels. On the one hand, this may be due to the bacterial composition of estrobolome, since bacteria with β-glucuronidase activity favour estrogens in a deconjugated state, which may ultimately lead to pathologies, including breast cancer. On the other hand, it has been shown that these changes in intestinal microbiota stimulate the kynurenine pathway, moving tryptophan away from the melatonergic pathway, thereby reducing circulating melatonin levels. Due to the fact that melatonin has antiestrogenic properties, it affects active and inactive estrogen levels. These changes increase the risk of developing breast cancer. Additionally, melatonin stimulates the differentiation of preadipocytes into adipocytes, which have low estrogen levels due to the fact that adipocytes do not express aromatase. Consequently, melatonin also reduces the risk of breast cancer. However, more studies are needed to determine the relationship between microbiota, melatonin, and breast cancer, in addition to clinical trials to confirm the sensitizing effects of melatonin to chemotherapy and radiotherapy, and its ability to ameliorate or prevent the side effects of these therapies.

Melatonin inhibits lipid accumulation to repress prostate cancer progression by mediating the epigenetic modification of CES1

BACKGROUND

Androgen deprivation therapy (ADT) is the main clinical treatment for patients with advanced prostate cancer (PCa). However, PCa eventually progresses to castration-resistant prostate cancer (CRPC), largely because of androgen receptor variation and increased intratumoral androgen synthesis. Several studies have reported that one abnormal lipid accumulation is significantly related to the development of PCa. Melatonin (MLT) is a functionally pleiotropic indoleamine molecule and a key regulator of energy metabolism. The aim of our study is finding the links between CRPC and MLT and providing the basis for MLT treatment for CRPC.

METHODS

We used animal CRPC models with a circadian rhythm disorder, and PCa cell lines to assess the role of melatonin in PCa.

RESULTS

We demonstrated that MLT treatment inhibited tumor growth and reversed enzalutamide resistance in animal CRPC models with a circadian rhythm disorder. A systematic review and meta-analysis demonstrated that MLT is positively associated with an increased risk of developing advanced PCa. Restoration of carboxylesterase 1 (CES1) expression by MLT treatment significantly reduced lipid droplet (LD) accumulation, thereby inducing apoptosis by increasing endoplasmic reticulum stress, reducing de novo intratumoral androgen synthesis, repressing CRPC progression and reversing the resistance to new endocrine therapy. Mechanistic investigations demonstrated that MLT regulates the epigenetic modification of CES1. Ces1-knockout (Ces-/- ) mice verified the important role of endogenous Ces1 in PCa.

CONCLUSIONS

Our findings provide novel preclinical and clinical information about the role of melatonin in advanced PCa and characterize the importance of enzalutamide combined with MLT administration as a therapy for advanced PCa.

Melatonin protects against apoptosis of megakaryocytic cells via its receptors and the AKT/mitochondrial/caspase pathway

Clinical studies have shown that melatonin lowers the frequency of thrombocytopenia in patients with cancer undergoing radiotherapy or chemotherapy. Here, we investigated the mechanisms by which melatonin promotes platelet formation and survival. Our results show that melatonin exerted protective effects on serum-free induced apoptosis of CHRF megakaryocytes (MKs). Melatonin promoted the formation of MK colony forming units (CFUs) in a dose-dependent manner. Using doxorubicin-treated CHRF cells, we found that melatonin rescued G2/M cell cycle arrest and cell apoptosis induced by doxorubicin. The expression of p-AKT was increased by melatonin treatment, an effect that was abolished by melatonin receptor blocker. In addition, we demonstrated that melatonin enhanced the recovery of platelets in an irradiated mouse model. Megakaryopoiesis was largely preserved in melatonin-treated mice. We obtained the same results in vivo from bone marrow histology and CFU-MK formation assays. Melatonin may exert these protective effects by directly stimulating megakaryopoiesis and inhibiting megakaryocyte apoptosis through activation of its receptors and AKT signaling.

Deciphering the Molecular Basis of Melatonin Protective Effects on Breast Cells Treated with Doxorubicin: TWIST1 a Transcription Factor Involved in EMT and Metastasis, a Novel Target of Melatonin

Melatonin mitigates cancer initiation, progression and metastasis through inhibition of both the synthesis of estrogens and the transcriptional activity of the estradiol-ER (Estrogen receptor) complex in the estrogen-dependent breast cancer cell line MCF-7. Moreover, melatonin improves the sensitivity of MCF-7 to chemotherapeutic agents and protects against their side effects. It has been described that melatonin potentiates the anti-proliferative effects of doxorubicin; however, the molecular changes involving gene expression and the activation/inhibition of intracellular signaling pathways remain largely unknown. Here we found that melatonin enhanced the anti-proliferative effect of doxorubicin in MCF-7 but not in MDA-MB-231 cells. Strikingly, doxorubicin treatment induced cell migration and invasion, and melatonin effectively counteracted these effects in MCF-7 but not in estrogen-independent MDA-MB-231 cells. Importantly, we describe for the first time the ability of melatonin to downregulate TWIST1 (Twist-related protein 1) in estrogen-dependent but not in estrogen-independent breast cancer cells. Combined with doxorubicin, melatonin inhibited the activation of p70S6K and modulated the expression of breast cancer, angiogenesis and clock genes. Moreover, melatonin regulates the levels of TWIST1-related microRNAs, such as miR-10a, miR-10b and miR-34a. Since TWIST1 plays a pivotal role in the epithelial to mesenchymal transition, acquisition of metastatic phenotype and angiogenesis, our results suggest that inhibition of TWIST1 by melatonin might be a crucial mechanism of overcoming resistance and improving the oncostatic potential of doxorubicin in estrogen-dependent breast cancer cells.

Adjuvant chemotherapy with melatonin for targeting human cancers: A review

Melatonin is a multifunctional hormone that has long been known for its antitumoral effects. An advantage of the application of melatonin in cancer therapy is its ability to differentially influence tumors from normal cells. In this review, the roles of melatonin adjuvant therapy in human cancer are discussed. Combination of melatonin with chemotherapy could provide synergistic antitumoral outcomes and resolve drug resistance in affected patients. This combination reduces the dosage for chemotherapeutic agents with the subsequent attenuation of side effects related to these drugs on normal cells around tumor and on healthy organs. The combination therapy increases the rate of survival and improves the quality of life in affected patients. Cancer cell viability is reduced after application of the combinational melatonin therapy. Melatonin does all these functions by adjusting the signals involved in cancer progression, re-establishing the dark/light circadian rhythm, and disrupting the redox system for cancer cells. To achieve effective therapeutic outcomes, melatonin concentration along with the time of incubation for this indoleamine needs to be adjusted. Importantly, a special focus is required to be made on choosing an appropriate chemotherapy agent for using in combination with melatonin. Because of different sensitivities of cancer cells for melatonin combination therapy, cancer-specific targeted therapy is also needed to be considered. For this review, the PubMed database was searched for relevant articles based on the quality of journals, the novelty of articles published by the journals, and the number of citations per year focusing only on human cancers.

Melatonin: An Anti-Tumor Agent in Hormone-Dependent Cancers

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone synthesized and secreted by the pineal gland mainly during the night, since light exposure suppresses its production. Initially, an implication of this indoleamine in malignant disease was described in endocrine-responsive breast cancer. Data from several clinical trials and multiple experimental studies performed both in vivo and in vitro have documented that the pineal hormone inhibits endocrine-dependent mammary tumors by interfering with the estrogen signaling-mediated transcription, therefore behaving as a selective estrogen receptor modulator (SERM). Additionally, melatonin regulates the production of estradiol through the control of the enzymes involved in its synthesis, acting as a selective estrogen enzyme modulator (SEEM). Many more mechanisms have been proposed during the past few years, including signaling triggered after activation of the membrane melatonin receptors MT-1 and MT-2, or else intracellular actions targeting molecules such as calmodulin, or binding intranuclear receptors. Similar results have been obtained in prostate (regulation of enzymes involved in androgen synthesis and modulation of androgen receptor levels and activity) and ovary cancer. Thus, tumor metabolism, gene expression, or epigenetic modifications are modulated, cell growth is impaired and angiogenesis and metastasis are inhibited. In the last decade, many more reports have demonstrated that melatonin is a promising adjuvant molecule with many potential beneficial consequences when included in chemotherapy or radiotherapy protocols designed to treat endocrine-responsive tumors. Therefore, in this state-of-the-art review, we aim to compile the knowledge about the oncostatic actions of the indoleamine in hormone-dependent tumors, and the latest findings concerning melatonin actions when administered in combination with radio- or chemotherapy in breast, prostate, and ovary cancers. As melatonin has no toxicity, it may be well deserve to be considered as an endogenously generated agent helpful in cancer prevention and treatment.

Antioxidants as precision weapons in war against cancer chemotherapy induced toxicity - Exploring the armoury of obscurity

Cancer is the leading cause of mortality worldwide, accounting for almost 13% of deaths in the world. Among the conventional cancer treatments, chemotherapy is most frequently carried out to treat malignant cancer rather than localised lesions which is amenable to surgery and radiotherapy. However, anticancer drugs are associated with a plethora of side effects. Each drug, within every class, has its own set of adverse reactions which may cause patient incompliance and deterioration of the quality of life. One of the major causes of adverse reactions, especially for drugs targeting DNA, is the excessive production of reactive oxygen species (ROS) and subsequent build up of oxidative stress. To curb these undesired side effects, several dietary supplements have been tested, amongst which antioxidants have gained increasing popularity as adjuvant in chemotherapy. However, many oncologists discourage the use of antioxidant rich food supplements because these may interfere with the modalities which kill cancer by generating free radicals. In the present review, all studies reporting concomitant use of several antioxidants with chemotherapy are indiscriminately included and discussed impartially.

The effect of supplementation of thirteen different antioxidants and their analogues as a single agent or in combination with chemotherapy has been compiled in this article. The present review encompasses a total of 174 peer-reviewed original articles from 1967 till date comprising 93 clinical trials with a cumulative number of 18,208 patients, 56 animal studies and 35 in vitro studies. Our comprehensive data suggests that antioxidant has superior potential of ameliorating chemotherapeutic induced toxicity. Antioxidant supplementation during chemotherapy also promises higher therapeutic efficiency and increased survival times in patients.

Should Patients Undergoing Chemotherapy and Radiotherapy Be Prescribed Antioxidants?

In September 2005, CA: A Cancer Journal for Clinicians published a warning by Gabriella D’Andrea, MD, against the concurrent use of antioxidants with radiotherapy and chemotherapy. However, several deficiencies of the CA article soon became apparent, not least the selective omission of prominent studies that contradicted the author’s conclusions. While acknowledging that only large-scale, randomized trials could provide a valid basis for therapeutic recommendations, the author sometimes relied on laboratory rather than clinical data to support her claim that harm resulted from the concurrent use of antioxidants and chemotherapy. She also sometimes extrapolated from chemoprevention studies rather than those on the concurrent use of antioxidants per se. The article overstated the degree to which the laboratory data diverged in regard to the safety and efficacy of antioxidant therapy: in fact, the preponderance of data suggests a synergistic or at least harmless effect with most high-dose dietary antioxidants and chemotherapy. The practical recommendations made in the article to avoid the general class of antioxidants during chemotherapy are inconsistent, in that if antioxidants were truly a threat to the efficacy of standard therapy, antioxidant-rich foods, especially fruits and vegetables, ought also be proscribed during treatment. Yet no such recommendation is made. Furthermore, the wide-scale use by both medical and radiation oncologists of synthetic antioxidants (eg, amifostine) to control the adverse effects of cytotoxic treatments is similarly overlooked. In sum, this CA article is incomplete: there is far more information available regarding antioxidant supplements as an appropriate adjunctive cancer therapy than is acknowledged. Patients would be well advised to seek the opinion of physicians who are adequately trained and experienced in the intersection of 2 complex fields, that is, chemotherapeutics and nutritional oncology. Physicians whose goal is comprehensive cancer therapy should refer their patients to qualified integrative practitioners who have such training and expertise to guide patients. A blanket rejection of the concurrent use of antioxidants with chemotherapy is not justified by the preponderance of evidence at this time and serves neither the scientific community nor cancer patients.

The therapeutic application of melatonin in supportive care and palliative medicine

Melatonin is a hormone produced mainly in the pineal gland. Plasma levels exhibit a circadian variation with the highest concentration occurring at night. The human biologic effects of melatonin depend upon the time of day it is made available. One of these effects is the setting and resetting of circadian clocks (chronobiotic effect). Additionally, it may be a potent antioxidant and immunomodulator and has been shown to have anti-tumor, anticytokine, anti-insomnia, and anticachexia effects. Melatonin has also been shown to improve survival and performance status in patients with advanced cancer. Objective tumor response occurs with melatonin alone or when combined with interleukin-2 (IL-2). Further, melatonin reduces radiation- and chemotherapeutic-induced toxicity. Symptomatic and circadian disruption is linked to increased cancer risk. The chronobiotic capacity of melatonin to reset circadian clocks may provide a verifiable strategy to reduce cancer risk and enhance quality of life by diminishing cancer-induced circadian disruption.

Survey of Policies and Guidelines on Antioxidant Use for Cancer Prevention, Treatment, and Survivorship in North American Cancer Centers: What Do Institutions Perceive as Evidence?

BACKGROUND

Health care policies and guidelines that are clear and consistent with research evidence are important for maximizing clinical outcomes. To determine whether cancer centers in Canada and the United States had policies and/or guidelines about antioxidant use, and whether policies were aligned with the evidence base, we reviewed current research evidence in the field, and we undertook a survey of the policies and guidelines on antioxidant use at cancer institutions across North America.

METHODS

A survey of policies and guidelines on antioxidant use and the development and communication of the policies and guidelines was conducted by contacting cancer institutions in North America. We also conducted a Website search for each institution to explore any online resources.

RESULTS

Policies and guidelines on antioxidant use were collected from 78 cancer institutions. Few cancer institutions had policies (5%) but most provided guidelines (69%). Antioxidants from diet were generally encouraged at cancer institutions, consistent with the current research evidence. In contrast, specific antioxidant supplements were generally not recommended at cancer institutions. Policies and guidelines were developed using evidence-based methods (53%), by consulting another source (35%), or through discussions/conference (26%), and communicated mainly through online resources (65%) or written handouts (42%). For cancer institutions that had no policy or guideline on antioxidants, lack of information and lack of time were the most frequently cited reasons.

CONCLUSIONS

Policies and guidelines on antioxidants from diet were largely consistent with the research evidence. Policies and guidelines on antioxidant supplements during treatment were generally more restrictive than the research evidence might suggest, perhaps due to the specificity of results and the inability to generalize findings across antioxidants, adding to the complexity of their optimal and safe use. Improved communication of comprehensive research evidence to cancer institutions may aid in the development of more evidence-based policies and guidelines.

Melatonin uses in oncology: breast cancer prevention and reduction of the side effects of chemotherapy and radiation

INTRODUCTION

The possible oncostatic properties of melatonin on different types of neoplasias have been studied especially in hormone-dependent adenocarcinomas. Despite the promising results of these experimental investigations, the use of melatonin in breast cancer treatment in humans is still uncommon.

AREAS COVERED

This article reviews the usefulness of this indoleamine for specific aspects of breast cancer management, particularly in reference to melatonin's antiestrogenic and antioxidant properties: i) treatments oriented to breast cancer prevention, especially when the risk factors are obesity, steroid hormone treatment or chronodisruption by exposure to light at night (LAN); ii) treatment of the side effects associated with chemo- or radiotherapy.

EXPERT OPINION

The clinical utility of melatonin depends on the appropriate identification of its actions. Because of its SERM (selective estrogen receptor modulators) and SEEM (selective estrogen enzyme modulators) properties, and its virtual absence of contraindications, melatonin could be an excellent adjuvant with the drugs currently used for breast cancer prevention (antiestrogens and antiaromatases). The antioxidant actions also make melatonin a suitable treatment to reduce oxidative stress associated with chemotherapy, especially with anthracyclines, and radiotherapy.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Use of antioxidant supplements during breast cancer treatment: a comprehensive review

PURPOSE

An estimated 45-80% of breast cancer patients use antioxidant supplements after diagnosis, and use of antioxidant supplements during breast cancer treatment is common. Dietary supplements with antioxidant effects include vitamins, minerals, phytonutrients, and other natural products. We conducted a comprehensive review of literature on the associations between antioxidant supplement use during breast cancer treatment and patient outcomes.

METHODS

Inclusion criteria were: two or more subjects; clinical trial or observational study design; use of antioxidant supplements (vitamin C, vitamin E, antioxidant combinations, multivitamins, glutamine, glutathione, melatonin, or soy isoflavones) during chemotherapy, radiation therapy, and/or hormonal therapy for breast cancer as exposures; treatment toxicities, tumor response, recurrence, or survival as outcomes.

RESULTS

We identified 22 articles that met those criteria. Their findings did not support any conclusions regarding the effects of individual antioxidant supplements during conventional breast cancer treatment on toxicities, tumor response, recurrence, or survival. A few studies suggested that antioxidant supplements might decrease side effects associated with treatment, including vitamin E for hot flashes due to hormonal therapy and glutamine for oral mucositis during chemotherapy. Underpowered trials suggest that melatonin may enhance tumor response during treatment.

CONCLUSION

The evidence is currently insufficient to inform clinician and patient guidelines on the use of antioxidant supplements during breast cancer treatment. Thus, well designed clinical trials and observational studies are needed to determine the short- and long-term effects of such agents.

Melatonin reduced volume of cerebral infarct induced by photothrombosis in wild-type mice, not in Cyclooxygenase-1 gene knockout mice

Cyclooxygenase (COX) is crucial in inflammation and plays important role in cerebral ischemia. Antiinflammatory effects of melatonin have been verified in previous studies. In this study, cerebral blood flow (CBF) was monitored during operation, infarct volume (IFV) was determined with 5-triphenyltetrazolium chloride (TTC) staining and MR image, and neurological functions were evaluated with turn in an alley and fall pole test in both COX1-gene knockout and wide-type mice with or without melatonin administration 3 days after photothrombosis. CBF reduction, IFV and neurological deficits were not significantly different in COX-1 wild-type and COX-1 knockout mice. Melatonin (15 mg/kg) intraperitoneal injection decreased the CBF reduction, IFV and the latency to turn in an alley in COX-1 wide-type mice, whereas the neuroprotective effect of melatonin was attenuated in COX-1 knockout mice. We concluded that melatonin reduced susceptibility to photothrombotic stroke. COX-1 gene knockout does not alter the susceptibility to cerebral ischemia caused by photothrombosis. COX-1 plays an important role in the pathway of the protection of melatonin.

Associations among Salivary Cortisol, Melatonin, Catecholamines, Sleep Quality and Stress in Women with Breast Cancer and Healthy Controls

Dysregulations in several biological systems in breast cancer patients have been reported, including abnormalities in endocrine and sympathetic nervous system indices, as well as psychological disturbances and sleep disorders. The purpose of this exploratory study was to compare women with breast cancer to healthy control women on measures of salivary cortisol, urinary catecholamines, overnight urinary melatonin, and self-reported sleep quality, symptoms of stress, depression, anxiety and mood disturbance, to determine if discernable patterns of dysregulations across systems were apparent. Thirty-three women were tested in each group, with an average age of approximately 52 years, primarily Caucasian and well-educated. Forty percent of the women with breast cancer had stage 2 disease and they were an average of 1.36 years post-diagnosis. Women with breast cancer had significantly higher levels of disturbance on all the psychological indices, but there were no differences between groups on any of the biological measures, with the exception that the control women had higher dopamine values than the participants with breast cancer. None of the psychological scores were correlated with the biological measures. These results are consistent with other studies of early-stage breast cancer and highlight the importance of considering disease characteristics when investigating endocrine and sympathetic nervous system functioning.

Transdermal delivery of a pineal hormone: melatonin via elastic liposomes

Melatonin (MT) is a good candidate for transdermal delivery considering its short biological half-life, low molecular weight and a variable oral absorption. The objective of this work was to develop a novel formulation of melatonin for its efficient transdermal delivery. Melatonin loaded elastic liposomal formulation was prepared, characterized and the effect of this developed formulation on the in vitro permeation of melatonin across human cadaver skin was investigated, using a locally fabricated Franz diffusion cell. Skin permeation potential of the developed formulation was assessed using confocal laser scanning microscopy (CLSM), which revealed an enhanced permeation of the formulation to the deeper layers of the skin (up to 180 microm) following channel like pathways. Skin permeation profile of melatonin through elastic liposomal formulations was observed and the investigations revealed an enhanced transdermal flux (51.2+/-2.21 microg/cm(2)/h), decreased lag time (1.1h) and an optimum permeability coefficient (15.06+/-0.52 cm/h) for melatonin. The obtained flux was nearly 5 and 12.3 times higher than conventional liposomal and plain drug solution, respectively (P<0.005). Our result suggests the feasibility of elastic liposomal system for transdermal delivery of melatonin thereby eliminating the limitations of long lag time and poor skin permeation associated with the drug.

Potentiel thérapeutique de la mélatonine dans la prise en charge de la pathologie cancéreuse

Melatonin is a small lipophile molecule, essentially secreted by pineal gland. The synthesis of this hormone shows a circadian pattern with a peak around 2-3 hours am. Many melatonin receptors are found in the body, which explains its multiple functions as biological rhythms resynchronisation, sleep induction, vasoregulation and even immunomodulation. Many experiments realised in this field have permit to discover different interactions between melatonin and the immune system, and especially the link which exists between melatonin and the fight against cancer via the immune system. Phase II studies reported a decrease of thrombocytopenia, an increase of some cytokines rate and an increase of objective responses in cancer patients. In order to confirm these results and to lead further research, we propose to realise a phase II randomised study melatonin versus placebo in metastatic breast cancer patients after two lines of treatment.

Herbs or natural products that decrease cancer growth part one of a four-part series

PURPOSE/OBJECTIVES

To provide evidence-based research information about 31 herbs and natural products that have shown potential in early research to decrease cancer growth or as adjuncts with cancer treatment.

DATA SOURCES

Names of herbs and natural products with potential to decrease cancer growth have been selected from listings in the Natural Medicines Comprehensive Database and Lawrence Review of Natural Products-Monograph System. Information about these herbs has been found in evidence-based studies cited in references.

DATA SYNTHESIS

In preliminary studies, 31 herbs and natural products appear to have potential for cancer treatment.

CONCLUSIONS

This preliminary evidence may be useful to healthcare professionals and patients with cancer.

IMPLICATIONS FOR NURSING

The information in this article is designed to provide quick access for healthcare professionals working in clinical oncology. Oncology nurses who have this information can become resources for patients and other healthcare professionals.

Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress and levels of cortisol, dehydroepiandrosterone sulfate (DHEAS) and melatonin in breast and prostate cancer outpatients

OBJECTIVES

This study investigated the relationships between a mindfulness-based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, and levels of cortisol, dehydroepiandrosterone-sulfate (DHEAS) and melatonin.

METHODS

Fifty-nine patients with breast cancer and 10 with prostate cancer enrolled in an eight-week Mindfulness-Based Stress Reduction (MBSR) program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life, mood, stress, and the hormone measures of salivary cortisol (assessed three times/day), plasma DHEAS, and salivary melatonin were assessed pre- and post-intervention.

RESULTS

Fifty-eight and 42 patients were assessed pre- and post-intervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality, but these improvements were not significantly correlated with the degree of program attendance or minutes of home practice. No significant improvements were seen in mood disturbance. Improvements in quality of life were associated with decreases in afternoon cortisol levels, but not with morning or evening levels. Changes in stress symptoms or mood were not related to changes in hormone levels. Approximately 40% of the sample demonstrated abnormal cortisol secretion patterns both pre- and post-intervention, but within that group patterns shifted from "inverted-V-shaped" patterns towards more "V-shaped" patterns of secretion. No overall changes in DHEAS or melatonin were found, but nonsignificant shifts in DHEAS patterns were consistent with healthier profiles for both men and women.

CONCLUSIONS

MBSR program enrollment was associated with enhanced quality of life and decreased stress symptoms in breast and prostate cancer patients, and resulted in possibly beneficial changes in hypothalamic-pituitary-adrenal (HPA) axis functioning. These pilot data represent a preliminary investigation of the relationships between MBSR program participation and hormone levels, highlighting the need for better-controlled studies in this area.

Melatonin: reducing the toxicity and increasing the efficacy of drugs

Melatonin (N-acetyl-5-methoxytryptamine) is a molecule with a very wide phylogenetic distribution from plants to man. In vertebrates, melatonin was initially thought to be exclusively of pineal origin recent studies have shown, however, that melatonin synthesis may occur in a variety of cells and organs. The concentration of melatonin within body fluids and subcellular compartments varies widely, with blood levels of the indole being lower than those at many other sites. Thus, when defining what constitutes a physiological level of melatonin, it must be defined relative to a specific compartment. Melatonin has been shown to have a variety of functions, and research in the last decade has proven the indole to be both a direct free radical scavenger and indirect antioxidant. Because of these actions, and possibly others that remain to be defined, melatonin has been shown to reduce the toxicity and increase the efficacy of a large number of drugs whose side effects are well documented. Herein, we summarize the beneficial effects of melatonin when combined with the following drugs: doxorubicin, cisplatin, epirubicin, cytarabine, bleomycin, gentamicin, ciclosporin, indometacin, acetylsalicylic acid, ranitidine, omeprazole, isoniazid, iron and erythropoietin, phenobarbital, carbamazepine, haloperidol, caposide-50, morphine, cyclophosphamide and L-cysteine. While the majority of these studies were conducted using animals, a number of the investigations also used man. Considering the low toxicity of melatonin and its ability to reduce the side effects and increase the efficacy of these drugs, its use as a combination therapy with these agents seems important and worthy of pursuit.

Studies on the anti-inflammatory and anti-nociceptive effects of melatonin in the rat

The present study aimed to evaluate the anti-inflammatory and anti-nociceptive effects of melatonin in the rat. Acute inflammation was induced by sub-plantar injection of carrageenan (1%) in the rat hind paw. The rats received vehicle or drug 30 min before carrageenan administration and were evaluated for paw oedema at 1, 2, 3, and 4 h post-carrageenan. The induced inflammation and the formation of oedema were determined by measurement of the paw thickness. Nociception was tested by determining vocalization following electrical stimulation of the tail. Given intraperitoneally (i.p.) 30 min before carrageenan, melatonin caused significant and a dose-dependent reduction of hind paw swelling induced by carrageenan. At doses of 0.5 and 1 mg kg(-1), melatonin inhibited the carrageenan-induced oedema by 20.5 and 29.6% versus control values at 4 h post-carrageenan, respectively. Melatonin (0.5 and 1 mg kg(-1), i.p.) 30 min beforehand displayed anti-nociceptive effect in the electric stimulation of the rat tail test, increasing nociceptive thresholds to electrically-induced pain at 4 h post-treatment by 29.6 and 39.5%, respectively. Melatonin given simultaneously with the non-selective COX-1 and COX-2 inhibitor indomethacin (5 mg kg(-1), i.p.) 30 min prior to carrageenan, enhanced the anti-inflammatory effect of the latter in the carrageenan-induced paw oedema model by 23%. Melatonin (0.5 mg kg(-1), i.p.) increased the anti-nociceptive effect of indomethacin (5 mg kg(-1), i.p.). Meanwhile, the anti-inflammatory and anti-nociceptive effect of the highly selective COX-2 inhibitor rofecoxib (2.25 mg kg(-1), i.p.) was only slightly increased by melatonin administration at 0.5 mg kg(-1). Melatonin enhanced the anti-inflammatory effect of cysteamine (300 mg kg(-1), s.c.) in the carrageenan-induced paw oedema. Melatonin (20 and 40 microg per paw) given prior to carrageenan into the rat hind paw was devoid of anti-inflammatory effect. These results indicate that melatonin possesses anti-inflammatory and anti-nociceptive properties in the rat and enhance those of indomethacin. This effect is likely to be centrally mediated.

Melatonin: from basic research to cancer treatment clinics

Melatonin, the chief secretory product of the pineal gland, is a direct free radical scavenger, an indirect antioxidant, as well as an important immunomodulatory agent. In both in vitro and in vivo investigations, melatonin protected healthy cells from radiation-induced and chemotherapeutic drug-induced toxicity. Furthermore, several clinical studies have demonstrated the potential of melatonin, either alone or in combination with traditional therapy, to yield a favorable efficacy to toxicity ratio in the treatment of human cancers. This study reviews the literature from laboratory investigations that document the antioxidant and oncostatic actions of melatonin and summarizes the evidence regarding the potential use of melatonin in cancer treatment. This study also provides rationale for the design of larger translational research-based clinical trials.

Disruption of mitochondrial respiration by melatonin in MCF-7 cells

Clinical and laboratory studies have provided evidence of oncostatic activity by the pineal neurohormone melatonin. However, these studies have not elucidated its mechanism of action. The following series of MCF-7 breast tumor cell studies conducted in the absence of exogenous steroid hormones provide evidence for a novel mechanism of oncostatic activity by this endogenous hormone. We observed a 40--60% loss of MCF-7 cells after 20-h treatment with 100 nM melatonin, which confirmed and extended previous reports of its oncostatic potency. Interestingly, there were no observed changes in tritiated thymidine uptake, suggesting a lack of effect on cell cycle/nascent DNA synthesis. Further evidence of a cytocidal effect came from morphologic observations of acute cell death and autophagocytosis accompanied by degenerative changes in mitochondria. Studies of mitochondrial function via standard polarography revealed a significant increase in oxygen consumption in melatonin-treated MCF-7 cells. Enzyme-substrate studies of electron transport chain (complex IV) activity in detergent permeabilized cells demonstrated a concomitant 53% increase (p < 0.01) in cytochrome c oxidase activity. Additional studies of succinate dehydrogenase activity (complex II) as determined by reduction of (3-4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide demonstrated a significant increase (p < 0.05) in melatonin-treated cells and further confirmed the accelerated ET activity. Finally, there was a 64% decrease (p < 0.05) in cellular ATP levels in melatonin-treated cells. The G-protein-coupled melatonin receptor antagonist luzindole abrogated the cytotoxic and mitochondrial effects. These studies suggest a receptor-modulated pathway of cytotoxicity in melatonin-treated MCF-7 tumor cells with apparent uncoupling of oxidative phosphorylation.