HER2 Support Group Forums - View Single Post - Melatonin treatment in animals = Ablation /ovary removal !!!!!!!!!!!!!!!!!!!!!

R.B. · 07-29-2006, 04:59 PM

More on same.

RB

http://www.ncbi.nlm.nih.gov/entrez/q...ids=156834691:

J Pineal Res. 2005 Mar;38(2):136-42.Click here to read Links
Melatonin modulates aromatase activity in MCF-7 human breast cancer cells.

* Cos S,
* Martinez-Campa C,
* Mediavilla MD,
* Sanchez-Barcelo EJ.

Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain.

Most of the current knowledge about the mechanisms by which melatonin inhibits the growth of breast cancer cells point to an interaction of melatonin with estrogen-responsive pathways, thus behaving as an antiestrogenic hormone. However, a possible effect of melatonin on the local synthesis of estrogens had not been examined. The objective of this work was to study whether melatonin may modify the aromatase activity in MCF-7 breast cancer cells thus modulating the local estrogen biosynthesis. In MCF-7 cells cultured with testosterone in estradiol-free media, melatonin (1 nM) counteracts the testosterone-induced cell proliferation dependent on the local biosynthesis of estrogens from testosterone by the aromatase activity of the cells. We found that melatonin reduces the aromatase activity (measured by the tritiated water release assay) of MCF-7 cells both at basal conditions and when aromatase activity was stimulated by cAMP or cortisol. The greatest inhibition of the aromatase activity was obtained with 1 nm melatonin, the same concentration that gives the highest antiproliferative and anti-invasive effects of MCF-7 cells. Finally, by RT-PCR, we found that melatonin downregulates aromatase expression at the transcriptional level in the MCF-7 cells. We conclude that melatonin, at physiological concentrations, decreases aromatase activity and expression in MCF-7 cells. This aromatase inhibitory effect of melatonin, together with its already known antiestrogenic properties interacting with the estrogen-receptor, makes this indoleamine an interesting tool to be considered in the prevention and treatment of hormone-dependent mammary neoplasias.

PMID: 15683469 [PubMed - indexed for MEDLINE]
Related Links

* Melatonin inhibits the growth of DMBA-induced mammary tumors by decreasing the local biosynthesis of estrogens through the modulation of aromatase activity. [Int J Cancer. 2006] PMID: 16080194
* Endogenous aromatization of testosterone results in growth stimulation of the human MCF-7 breast cancer cell line. [J Steroid Biochem Mol Biol. 2005] PMID: 15748829
* Influence of melatonin on invasive and metastatic properties of MCF-7 human breast cancer cells. [Cancer Res. 1998] PMID: 9766668
* Keratinocyte growth factor (KGF) induces aromatase activity in cultured MCF-7 human breast cancer cells. [Anticancer Res. 1998] PMID: 9703907
* Melatonin enhances the inhibitory effect of aminoglutethimide on aromatase activity in MCF-7 human breast cancer cells. [Breast Cancer Res Treat. 2005] PMID: 16244789
* See

07-29-2006, 04:59 PM	#2
R.B. Senior Member Join Date: Mar 2006 Posts: 1,843	More on same. RB http://www.ncbi.nlm.nih.gov/entrez/q...ids=156834691: J Pineal Res. 2005 Mar;38(2):136-42.Click here to read Links Melatonin modulates aromatase activity in MCF-7 human breast cancer cells. * Cos S, * Martinez-Campa C, * Mediavilla MD, * Sanchez-Barcelo EJ. Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain. Most of the current knowledge about the mechanisms by which melatonin inhibits the growth of breast cancer cells point to an interaction of melatonin with estrogen-responsive pathways, thus behaving as an antiestrogenic hormone. However, a possible effect of melatonin on the local synthesis of estrogens had not been examined. The objective of this work was to study whether melatonin may modify the aromatase activity in MCF-7 breast cancer cells thus modulating the local estrogen biosynthesis. In MCF-7 cells cultured with testosterone in estradiol-free media, melatonin (1 nM) counteracts the testosterone-induced cell proliferation dependent on the local biosynthesis of estrogens from testosterone by the aromatase activity of the cells. We found that melatonin reduces the aromatase activity (measured by the tritiated water release assay) of MCF-7 cells both at basal conditions and when aromatase activity was stimulated by cAMP or cortisol. The greatest inhibition of the aromatase activity was obtained with 1 nm melatonin, the same concentration that gives the highest antiproliferative and anti-invasive effects of MCF-7 cells. Finally, by RT-PCR, we found that melatonin downregulates aromatase expression at the transcriptional level in the MCF-7 cells. We conclude that melatonin, at physiological concentrations, decreases aromatase activity and expression in MCF-7 cells. This aromatase inhibitory effect of melatonin, together with its already known antiestrogenic properties interacting with the estrogen-receptor, makes this indoleamine an interesting tool to be considered in the prevention and treatment of hormone-dependent mammary neoplasias. PMID: 15683469 [PubMed - indexed for MEDLINE] Related Links * Melatonin inhibits the growth of DMBA-induced mammary tumors by decreasing the local biosynthesis of estrogens through the modulation of aromatase activity. [Int J Cancer. 2006] PMID: 16080194 * Endogenous aromatization of testosterone results in growth stimulation of the human MCF-7 breast cancer cell line. [J Steroid Biochem Mol Biol. 2005] PMID: 15748829 * Influence of melatonin on invasive and metastatic properties of MCF-7 human breast cancer cells. [Cancer Res. 1998] PMID: 9766668 * Keratinocyte growth factor (KGF) induces aromatase activity in cultured MCF-7 human breast cancer cells. [Anticancer Res. 1998] PMID: 9703907 * Melatonin enhances the inhibitory effect of aminoglutethimide on aromatase activity in MCF-7 human breast cancer cells. [Breast Cancer Res Treat. 2005] PMID: 16244789 * See