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Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
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Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells

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Membrane-bound melatonin receptor MT1 down-regulates estrogen responsive genes in breast cancer cells

Rainer Girgert1, Volker Hanf, Günter Emons

  • 1Department of Obstetrics and Gynecology, University of Göttingen, Göttingen, Germany.

Journal of Pineal Research
|June 16, 2009
PubMed

Insights

Melatonin, a hormone, inhibits estrogen-driven breast cancer growth by affecting key genes. Its primary receptor, MT1, is crucial for these anti-estrogenic effects in cancer cells.

Area of Science:

  • Molecular Biology
  • Endocrinology
  • Oncology

Background:

  • Melatonin exhibits anti-estrogenic properties in estrogen receptor-positive (ER+) breast cancer cells.
  • The membrane-bound receptor MT1 is believed to mediate most of melatonin's cellular effects.
  • The role of the nuclear receptor RZRalpha in melatonin's action is still under investigation.

Purpose of the Study:

  • To investigate the role of melatonin receptors, particularly MT1, in mediating anti-estrogenic effects on breast cancer cells.
  • To examine the impact of melatonin on estrogen-responsive gene expression in different breast cancer cell lines.
  • To determine the correlation between melatonin receptor expression levels and the modulation of these genes.

Main Methods:

  • Utilized various breast cancer cell lines with differing estrogen receptor and melatonin receptor expression.
  • Analyzed the effect of melatonin on CREB-protein binding to the cAMP-responsive element of BRCA-1 in MCF-7Mel1a cells.
  • Measured the expression of estrogen-responsive genes (BRCA-1, p53, p21(WAF), c-myc) after estradiol and melatonin treatments.

Main Results:

  • Melatonin treatment reduced CREB-protein binding more significantly in MT1-transfected cells compared to parental cells.
  • Estradiol upregulated BRCA-1, p53, p21(WAF), and c-myc expression, which was nearly completely reversed by melatonin.
  • Higher MT1 expression correlated with a stronger reduction in estradiol-induced gene expression; RZRalpha expression showed no correlation.

Conclusions:

  • Melatonin exerts anti-estrogenic effects on breast cancer cells by downregulating key genes involved in cell proliferation.
  • The MT1 receptor plays a significant role in mediating melatonin's inhibitory effects on estrogen-responsive gene expression.
  • The nuclear receptor RZRalpha does not appear to be involved in melatonin's observed effects on these genes.

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