Related Experiment Video
Updated: Jul 7, 2026
Using Mouse Mammary Tumor Cells to Teach Core Biology Concepts: A Simple Lab Module
Published on: June 18, 2015
Selective estrogen enzyme modulator actions of melatonin in human breast cancer cells
A Gonzalez1, S Cos, C Martinez-Campa
1Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain.
Abstract:
Melatonin exerts oncostatic effects on different kinds of neoplasias, especially on estrogen-dependent mammary tumors. 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. The intratumoral production of estrogens in breast carcinoma tissue plays a pivotal role in the proliferation of mammary tumoral cells and its blockade is one of the main objectives of the treatment of breast cancer. The aim of the present work is centered on the study of the role of melatonin in the control of some enzymes involved in the formation and transformation of estrogens in human breast cancer cells. The present study demonstrates that melatonin, at physiologic concentrations, modulates the synthesis and transformation of biologically active estrogens in MCF-7 cells, through the inhibition of sulfatase (STS) and 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) activity and expression, enzymes involved in the estradiol formation in breast cancer cells. Physiologic concentrations of melatonin also stimulate the activity and expression of estrogen sulfotransferase (EST), the enzyme responsible for the formation of the biologically inactive estrogen sulfates. The level of EST mRNA steady-state of cells treated with melatonin was three times higher than that in control cells. These findings which document that melatonin has an inhibitory effect on STS and 17beta-HSD1 and a stimulatory effect on EST, in combination with its previously described antiaromatase effect, can open up new and interesting possibilities in clinical applications of melatonin in breast cancer.
Insights
Melatonin inhibits key enzymes (sulfatase and 17beta-HSD1) in estrogen formation and boosts estrogen inactivation in breast cancer cells. This suggests melatonin
Area of Science:
- Endocrinology
- Oncology
- Molecular Biology
Background:
- Melatonin exhibits oncostatic properties, particularly against estrogen-dependent breast cancers.
- Estrogen production within tumors fuels mammary cancer cell proliferation, making estrogen blockade a key therapeutic strategy.
- Melatonin's anti-cancer effects are linked to its interaction with estrogen-responsive pathways.
Purpose of the Study:
- To investigate melatonin's role in regulating enzymes involved in estrogen synthesis and metabolism in human breast cancer cells.
- To elucidate the impact of melatonin on key enzymes like sulfatase (STS), 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), and estrogen sulfotransferase (EST).
Main Methods:
- Treatment of MCF-7 human breast cancer cells with physiological concentrations of melatonin.
- Assay of enzyme activity and gene expression for STS, 17beta-HSD1, and EST.
- Quantification of EST mRNA steady-state levels.
Main Results:
- Melatonin significantly inhibited the activity and expression of sulfatase (STS) and 17beta-HSD1, enzymes crucial for estradiol formation.
- Melatonin stimulated both the activity and expression of estrogen sulfotransferase (EST), an enzyme that inactivates estrogens.
- EST mRNA levels were threefold higher in melatonin-treated cells compared to controls.
Conclusions:
- Melatonin modulates estrogen synthesis and transformation in breast cancer cells by inhibiting STS and 17beta-HSD1, and stimulating EST.
- These findings, coupled with melatonin's anti-aromatase effects, highlight its potential clinical applications in breast cancer treatment.
