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Therapeutic actions of melatonin in cancer: possible mechanisms

Srinivasan V, Spence DW, Pandi-Perumal SR, Trakht I, Cardinali DP

Integr Cancer Ther, 2008 Sep;7(3):189-203.
PMID: 18815150 DOI: 10.1177/1534735408322846

Melatonin is a phylogenetically well-preserved molecule with diverse physiological functions. In addition to its well-known regulatory control of the sleep/wake cycle, as well as circadian rhythms generally, melatonin is involved in immunomodulation, hematopoiesis, and antioxidative processes. Recent human and animal studies have now shown that melatonin also has important oncostatic properties. Both at physiological and pharmacological doses melatonin exerts growth inhibitory effects on breast cancer cell lines. In hepatomas, through its activation of MT1 and MT2 receptors, melatonin inhibits linoleic acid uptake, thereby preventing the formation of the mitogenic metabolite 1,3-hydroxyoctadecadienoic acid. In animal model studies, melatonin has been shown to have preventative action against nitrosodiethylamine (NDEA)-induced liver cancer. Melatonin also inhibits the growth of prostate tumors via activation of MT1 receptors thereby inducing translocation of the androgen receptor to the cytoplasm and inhibition of the effect of endogenous androgens. There is abundant evidence indicating that melatonin is involved in preventing tumor initiation, promotion, and progression. The anticarcinogenic effect of melatonin on neoplastic cells relies on its antioxidant, immunostimulating, and apoptotic properties. Melatonin's oncostatic actions include the direct augmentation of natural killer (NK) cell activity, which increases immunosurveillance, as well as the stimulation of cytokine production, for example, of interleukin (IL)-2, IL-6, IL-12, and interferon (IFN)-gamma. In addition to its direct oncostatic action, melatonin protects hematopoietic precursors from the toxic effect of anticancer chemotherapeutic drugs. Melatonin secretion is impaired in patients suffering from breast cancer, endometrial cancer, or colorectal cancer. The increased incidence of breast cancer and colorectal cancer seen in nurses and other night shift workers suggests a possible link between diminished secretion of melatonin and increased exposure to light during nighttime. The physiological surge of melatonin at night is thus considered a "natural restraint" on tumor initiation, promotion, and progression.
Immunomodulation by melatonin: its significance for seasonally occurring diseases

Srinivasan V, Spence DW, Trakht I, Pandi-Perumal SR, Cardinali DP, Maestroni GJ

Neuroimmunomodulation, 2008;15(2):93-101.
PMID: 18679047 DOI: 10.1159/000148191

Melatonin is not only synthesized by the pineal gland but also in many other organs and tissues of the body, particularly by lymphoid organs such as the bone marrow, thymus and lymphocytes. Melatonin participates in various functions of the body, among which its immunomodulatory role has assumed considerable significance in recent years. Melatonin has been shown to be involved in the regulation of both cellular and humoral immunity. Melatonin not only stimulates the production of natural killer cells, monocytes and leukocytes, but also alters the balance of T helper (Th)-1 and Th-2 cells mainly towards Th-1 responses and increases the production of relevant cytokines such as interleukin (IL)-2, IL-6, IL-12 and interferon-gamma. The regulatory function of melatonin on immune mechanisms is seasonally dependent. This fact may in part account for the cyclic pattern of symptom expression shown by certain infectious diseases, which become more pronounced at particular times of the year. Moreover, melatonin-induced seasonal changes in immune function have also been implicated in the pathogenesis of seasonal affective disorder and rheumatoid arthritis. The clinical significance of the seasonally changing immunomodulatory role of melatonin is discussed in this review.
Pathophysiology of depression: role of sleep and the melatonergic system

Srinivasan V, Pandi-Perumal SR, Trakht I, Spence DW, Hardeland R, Poeggeler B, et al.

Psychiatry Res, 2009 Feb 28;165(3):201-14.
PMID: 19181389 DOI: 10.1016/j.psychres.2007.11.020

Profound disturbances in sleep architecture occur in major depressive disorders (MDD) and in bipolar affective disorders. Reduction in slow wave sleep, decreased latency of rapid eye movement (REM) sleep and abnormalities in the timing of REM/non-REM sleep cycles have all been documented in patients with MDD. It is thus evident that an understanding of the basic mechanisms of sleep regulation is essential for an analysis of the pathophysiology of depressive disorders. The suprachiasmatic nucleus (SCN), which functions as the body's master circadian clock, plays a major role in the regulation of the sleep/wakefulness rhythm and interacts actively with the homeostatic processes that regulate sleep. The control of melatonin secretion by the SCN, the occurrence of high concentrations of melatonin receptors in the SCN, and the suppression of electrical activity in the SCN by melatonin all underscore the major influence which this neurohormone has in regulating the sleep/wake cycle. The transition from wakefulness to high sleep propensity is associated with the nocturnal rise of endogenous melatonin secretion. Various lines of evidence show that depressed patients exhibit disturbances in both the amplitude and shape of the melatonin secretion rhythm and that melatonin can improve the quality of sleep in these patients. The choice of a suitable antidepressant that improves sleep quality is thus important while treating a depressive disorder. The novel antidepressant agomelatine, which combines the properties of a 5-HT(2C) antagonist and a melatonergic MT(1)/MT(2) receptor agonist, has been found very effective for resetting the disturbed sleep/wake cycle and in improving the clinical status of MDD. Agomelatine has also been found useful in treating sleep problems and improving the clinical status of patients suffering from seasonal affective disorder.
Jet lag: therapeutic use of melatonin and possible application of melatonin analogs

Srinivasan V, Spence DW, Pandi-Perumal SR, Trakht I, Cardinali DP

Travel Med Infect Dis, 2008 Jan-Mar;6(1-2):17-28.
PMID: 18342269 DOI: 10.1016/j.tmaid.2007.12.002

Each year millions of travelers undertake long distance flights over one or more continents. These multiple time zone flights produce a constellation of symptoms known as jet lag. Familiar to almost every intercontinental traveler is the experience of fatigue upon arrival in a new time zone, but almost as problematic are a number of other jet lag symptoms. These include reduced alertness, nighttime insomnia, loss of appetite, depressed mood, poor psychomotor coordination and reduced cognitive skills, all symptoms which are closely affected by both the length and direction of travel. The most important jet lag symptoms are due to disruptions to the body's sleep/wake cycle. Clinical and pathophysiological studies also indicate that jet lag can exacerbate existing affective disorders. It has been suggested that dysregulation of melatonin secretion and occurrence of circadian rhythm disturbances may be the common links which underlie jet lag and affective disorders. Largely because of its regulatory effects on the circadian system, melatonin has proven to be highly effective for treating the range of symptoms that accompany transmeridian air travel. Additionally, it has been found to be of value in treating mood disorders like seasonal affective disorder. Melatonin acts on MT(1) and MT(2) melatonin receptors located in the hypothalamic suprachiasmatic nuclei, the site of the body's master circadian clock. Melatonin resets disturbed circadian rhythms and promotes sleep in jet lag and other circadian rhythm sleep disorders, including delayed sleep phase syndrome and shift-work disorder. Although post-flight melatonin administration works efficiently in transmeridian flights across less than 7-8 times zones, in the case longer distances, melatonin should be given by 2-3 days in advance to the flight. To deal with the unwanted side effects which usually accompany this pre-departure treatment (acute soporific and sedative effects in times that may not be wanted), the suppression of circadian rhythmicity by covering symmetrically the phase delay and the phase advance portions of the phase response curve for light, together with the administration of melatonin at local bedtime to resynchronize the circadian oscillator, have been proposed. The current view that sleep loss is a major cause of jet lag has focused interest on two recently developed pharmacological agents. Ramelteon and agomelatine are melatonin receptor agonists which, compared to melatonin itself, have a longer half-life and greater affinity for melatonin receptors and consequently are thought to hold promise for treating a variety of circadian disruptions.
Melatonin, environmental light, and breast cancer

Srinivasan V, Spence DW, Pandi-Perumal SR, Trakht I, Esquifino AI, Cardinali DP, et al.

Breast Cancer Res Treat, 2008 Apr;108(3):339-50.
PMID: 17541739

Although many factors have been suggested as causes for breast cancer, the increased incidence of the disease seen in women working in night shifts led to the hypothesis that the suppression of melatonin by light or melatonin deficiency plays a major role in cancer development. Studies on the 7,12-dimethylbenz[a]anthracene and N-methyl-N-nitrosourea experimental models of human breast cancer indicate that melatonin is effective in reducing cancer development. In vitro studies in MCF-7 human breast cancer cell line have shown that melatonin exerts its anticarcinogenic actions through a variety of mechanisms, and that it is most effective in estrogen receptor (ER) alpha-positive breast cancer cells. Melatonin suppresses ER gene, modulates several estrogen dependent regulatory proteins and pro-oncogenes, inhibits cell proliferation, and impairs the metastatic capacity of MCF-7 human breast cancer cells. The anticarcinogenic action on MCF-7 cells has been demonstrated at the physiological concentrations of melatonin attained at night, suggesting thereby that melatonin acts like an endogenous antiestrogen. Melatonin also decreases the formation of estrogens from androgens via aromatase inhibition. Circulating melatonin levels are abnormally low in ER-positive breast cancer patients thereby supporting the melatonin hypothesis for breast cancer in shift working women. It has been postulated that enhanced endogenous melatonin secretion is responsible for the beneficial effects of meditation as a form of psychosocial intervention that helps breast cancer patients.
Therapeutic potential of melatonin agonists

Cardinali DP, Pandi-Perumal SR, Srinivasan V, Spence DW, Trakht I

Expert Rev Endocrinol Metab, 2008 Mar;3(2):269-279.
PMID: 30764095 DOI: 10.1586/17446651.3.2.269

Melatonin, a hormone secreted by the pineal gland, has been successfully employed to improve sleep in both normal patients and insomniacs, and for the treatment of circadian rhythm sleep disorders. Melatonergic MT1 and MT2 receptors exist in high concentrations in the suprachiasmatic nucleus of the hypothalamus and have been shown to be instrumental for the sleep-promoting and circadian rhythm-regulating effects of melatonin. A lack of consistency among reports on the therapeutic efficacy of melatonin has been attributed to differences in melatonin's bioavailability and the short half-life of the hormone. In view of the need for longer acting melatonergic agonists that improve sleep efficiency without causing drug abuse or dependency, ramelteon (Rozerem™, Takeda) was developed. Ramelteon, which acts via MT1/MT2 melatonergic agonism, has been found clinically effective for improving total sleep time and sleep efficiency in insomniacs. Agomelatine (Valdoxan™, Servier) is another MT1/MT2 melatonergic agonist that also displays antagonist activity at 5-HT2C serotonin receptors. Agomelatine has been found effective in treating depression and sleep disorders in patients with major depressive disorder. A slow-release preparation of melatonin (Circadin™, Neurim) has been shown to be effective in treating sleep disorders in the elderly population.
Mapping Palliative Care Availability and Accessibility: A First Step to Eradicating Access Deserts in the Low- and Middle-Income Settings

Segarmurthy MV, Lim RB, Yeat CL, Ong YX, Othman S, Taher SW, et al.

J Palliat Care, 2023 Nov 19.
PMID: 37981855 DOI: 10.1177/08258597231214485

OBJECTIVE: Palliative care is unavailable and/or inaccessible for the majority of people in low- and middle-income countries (LMIC). This study aims to determine the availability and accessibility of palliative care services in Malaysia, a middle-income country that has made good progress toward universal health coverage (UHC).
METHOD: Publicly available data, and databases of registered palliative care services were obtained from governmental and nongovernmental sources. Google Maps and Rome2Rio web-based applications were used to assess geographical disparities by estimating the median distance, travel time, and travel costs from every Malaysian district to the closest palliative care service.
RESULTS: Substantial variations in availability, components, and accessibility (distance, time, and cost to access care) of palliative care services were observed. In the highly developed Central Region of Peninsular Malaysia, specialty care was available within 4 km whereas in the less-developed East Coast of Peninsular Malaysia, patients had to travel approximately 46 km. In the predominantly rural East Malaysia, basic palliative care services were 82 km away and, in some instances, where land connectivity was scarce, it took 2.5 h to access care via boat. The corresponding median travel costs were USD2 (RM9) and USD23 (RM114) in Peninsular Malaysia and East Malaysia.
CONCLUSION: The stark urban-rural divide in the availability and accessibility of palliative care services even in a setting that has made good progress toward UHC highlights the urgent need for decentralization of palliative care in the LMICs. This may be achieved by capacity building and task shifting in primary care and community settings.
Fulltext Augmented Package of Palliative Care for Women With Cervical Cancer: Responding to Refractory Suffering

Krakauer EL, Kane K, Kwete X, Afshan G, Bazzett-Matabele L, Ruthnie Bien-Aimé DD, et al.

JCO Glob Oncol, 2021 06;7:886-895.
PMID: 34115537 DOI: 10.1200/GO.21.00027

The essential package of palliative care for cervical cancer (EPPCCC), described elsewhere, is designed to be safe and effective for preventing and relieving most suffering associated with cervical cancer and universally accessible. However, it appears that women with cervical cancer, more frequently than patients with other cancers, experience various types of suffering that are refractory to basic palliative care such as what can be provided with the EPPCCC. In particular, relief of refractory pain, vomiting because of bowel obstruction, bleeding, and psychosocial suffering may require additional expertise, medicines, or equipment. Therefore, we convened a group of experienced experts in all aspects of care for women with cervical cancer, and from countries of all income levels, to create an augmented package of palliative care for cervical cancer with which even suffering refractory to the EPPCCC often can be relieved. The package consists of medicines, radiotherapy, surgical procedures, and psycho-oncologic therapies that require advanced or specialized training. Each item in this package should be made accessible whenever the necessary resources and expertise are available.
Fulltext Essential Package of Palliative Care for Women With Cervical Cancer: Responding to the Suffering of a Highly Vulnerable Population

Krakauer EL, Kane K, Kwete X, Afshan G, Bazzett-Matabele L, Ruthnie Bien-Aimé DD, et al.

JCO Glob Oncol, 2021 Jun;7:873-885.
PMID: 34115527 DOI: 10.1200/GO.21.00026

Women with cervical cancer, especially those with advanced disease, appear to experience suffering that is more prevalent, complex, and severe than that caused by other cancers and serious illnesses, and approximately 85% live in low- and middle-income countries where palliative care is rarely accessible. To respond to the highly prevalent and extreme suffering in this vulnerable population, we convened a group of experienced experts in all aspects of care for women with cervical cancer, and from countries of all income levels, to create an essential package of palliative care for cervical cancer (EPPCCC). The EPPCCC consists of a set of interventions, medicines, simple equipment, social supports, and human resources, and is designed to be safe and effective for preventing and relieving all types of suffering associated with cervical cancer. It includes only inexpensive and readily available medicines and equipment, and its use requires only basic training. Thus, the EPPCCC can and should be made accessible everywhere, including for the rural poor. We provide guidance for integrating the EPPCCC into gynecologic and oncologic care at all levels of health care systems, and into primary care, in countries of all income levels.
Fulltext Cervical Cancer-Associated Suffering: Estimating the Palliative Care Needs of a Highly Vulnerable Population

Krakauer EL, Kwete X, Kane K, Afshan G, Bazzett-Matabele L, Bien-Aimé DDR, et al.

JCO Glob Oncol, 2021 Jun;7:862-872.
PMID: 34115522 DOI: 10.1200/GO.21.00025

PURPOSE: To enable design of optimum palliative care for women with cervical cancer, we studied the most common types of suffering and their severity, prevalence, and duration.
METHODS: We first reviewed the literature on the major types, severity, prevalence, and duration of suffering associated with cervical cancer. We then conducted a modified Delphi process with experts in cervical cancer care to supplement the literature. For each type of suffering, we distinguished between decedents (those who die from cervical cancer in a given year) and nondecedents (those who have cervical cancer in a given year but do not die). By applying the suffering prevalence and duration estimates to the number of decedents, nondecedents, and family caregivers in 2017, we were able to estimate their palliative care needs and the intensity of palliative care needed to respond adequately to this suffering.
RESULTS: There is a high prevalence among decedents of moderate or severe pain (84%), vaginal discharge (66%), vaginal bleeding (61%), and loss of faith (31%). Among both decedents and nondecedents, there is a high prevalence of clinically significant anxiety (63% and 50%, respectively), depressed mood (52% and 38%, respectively), and sexual dysfunction (87% and 83%, respectively). Moderate or severe financial distress is prevalent among decedents, nondecedents, and family caregivers (84%, 74%, and 66%, respectively). More than 40% of decedents and nondecedents are abandoned by their intimate partners. Most patients experience some combination of moderate or severe physical, psychological, social, and spiritual suffering. In total, 258,649 decedents and 2,558,857 nondecedents needed palliative care in 2017, approximately 85% of whom were in low- and middle-income countries where palliative care is rarely accessible.
CONCLUSION: Among women with advanced cervical cancer, suffering is highly prevalent and often severe and multifaceted.

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