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The biologically active melatonin metabolite, 6-hydroxymelatonin (6-OHMel), is conjugated to form 6-hydroxymelatonin sulfate (6-OHMelS). To elucidate the role of the sulfotransferase (SULT) enzyme 1A1, considerably expressed in normal and malignant human breast cells, we measured the formation of
Melatonin inhibits human breast cancer cells stimulated with estrogen. This antiproliferative action depends on the presence of the estrogen receptor alpha (ERα) in the human MCF-7 cell line and is strictly dose-dependent. Since researchers concerned with melatonin and breast cancer have not
BACKGROUND
Breast cancer is a heterogeneous disease and is the leading cause of cancer-related deaths among women. Even after diagnosis, the prognosis cannot be concluded since patients can develop resistance to therapy, which favors tumor growth, invasion and metastasis. In e recent years, research
BACKGROUND
Circadian rhythms in plasma concentrations of many hormones and cytokines determine their effects on target cells.
METHODS
Circadian variations were studied in cortisol, melatonin, cytokines (basic fibroblast growth factor IbFGF], EGF, insulin-like growth factor-1 [IGF-1]), and a cytokine
The use of the conventional combination oral contraceptives (containing ethinyl-estradiol and a progestin) is associated with reduced risk of ovarian and endometrial cancer. However, prolonged use of these pills before first term pregnancy apparently increases the risk of pre menopausal breast
MCF-7 human breast cancer cells, which are estrogen receptor (ER)-positive and responsive to the mitogenic actions of estrogen, were used to examine the possible association between the growth-inhibitory activity of melatonin and its ability to modulate the estrogen-response pathway. Melatonin at
BACKGROUND
Insulin-like growth factor-I (IGF-I) is probably involved in promoting both normal and neoplastic cell growth, neoplastic transformation processes, angiogenesis, and neoplasma progression. On the other hand, one possible mechanism of the oncostatic action of melatonin is its influence on
A seasonal variation in the month of initial detection of breast cancer has been previously observed in pre-menopausal women, and it has been proposed that this may be due to cyclic changes in tumour growth mediated by the effects of melatonin on ovarian function. To investigate this possibility
Melatonin possesses anti-estrogenic effects on estrogen receptor expressing (ER+) breast cancer cells in culture by reducing cell cycle progression and cell proliferation. There is increasing agreement that on a cellular level the effects of melatonin are primarily induced by the membrane-bound
The role of the pineal as an oncostatic gland has been studied in animal models of tumorigenesis, especially on those concerning the mammary gland. The general conclusion is that experimental manipulations activating pineal gland, or the administration of melatonin, reduce the incidence and growth
The pineal hormone, melatonin, has been reported to have an inhibitory effect on the cell growth of human breast cancer. We have now assessed the interaction of melatonin with 5-fluorouracil (5-FU) on estrogen-sensitive MCF7 and estrogen-insensitive HBC4 cell lines. Melatonin inhibited MCF7 cell
Breast tumor incidence is compared in C3CF1 mice, receiving at one of 6 different circadian stages, daily injections of melatonin or of a vehicle or no treatment, the latter in a slightly cooler environment. Results are summarized when approximately 33% of all animals have a breast tumor. Vehicle
Serum melatonin and its main metabolic product 6-sulfatoxymelatonin were determined in 17 patients with breast cancer (BC) with either a fresh primary tumor (nine) or a secondary tumor (eight) as well as in four patients with untreated benign breast disease (controls). Circadian rhythms were
OBJECTIVE
Melatonin may influence directly tumor cells through the specific binding sites. The best known melatonin binding sites are membrane receptors. Recently, the participation of nuclear signalling via estrogen as well as RZR/ROR receptors in oncostatic action of melatonin on the breast cancer
BACKGROUND
The high rates of women's death from breast cancer occur due to acquired resistance by patients to certain treatments, enabling the recurrence and/or tumor growth, invasion and metastasis. It has been demonstrated that the presence of cancer stem cells in human tumors, as