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Updated: Mar 14, 2026
Mammosphere Formation Assay from Human Breast Cancer Tissues and Cell Lines
Published on: March 22, 2015
Evaluation of Melatonin Effect on Human Breast Cancer Stem Cells Using a Threedimensional Growth Method of
Juliana Ramos Lopes1, Mayume da Silva Kavagutti2, Felipe Arthur Faustino de Medeiros2
1Postgraduate program in Genetics, Universidade Estadual Paulista, UNESP/IBILCE, São José do Rio Preto, SP, Brazil. Cristovão Colombo, 2265, Zip Code: 15054-000, São José do Rio Preto, SP. Brazil.
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 responsible for recurrence and resistance to therapy. Studies have identified OCT4 as responsible for self-renewal and maintenance of pluripotency of stem cells. Thus, it is interesting to study potential drugs that target this specific population in breast cancer. Melatonin, appears to have oncostatic effects on cancer cells, however, little is known about its therapeutic effect on cancer stem cells.
Objective:
Evaluate the viability and the expression of OCT4 in breast cancer stem cells, MCF-7 and MDA-MB- 231, after melatonin treatment.
Method:
The cells were grown in a 3-dimensional model of mammospheres, representing the breast cancer stem cell population and treated or not with melatonin. The cell viability of mammospheres were evaluated by MTT assay and the OCT4 expression, a cancer stem cells marker, was verified by immunocitochemistry.
Results:
Our results demonstrated that the melatonin treatment decreased the cell viability of MCF-7 and MDAMB- 231 mammospheres. Furthermore, it was observed that in both cell lines, the expression of OCT4 was decreased in melatonin-treated cells compared to the control group.
Conclusions:
This fact suggests that melatonin is effective against breast cancer stem cells inhibiting the cell viability via OCT 4. Based on that, we believe that melatonin has a high potential to be used as an alternative treatment for breast cancer.
Insights
Melatonin effectively reduces breast cancer stem cell viability and OCT4 expression. This suggests melatonin may be a promising alternative treatment for breast cancer by targeting cancer stem cells.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Breast cancer mortality is high due to treatment resistance and recurrence.
- Cancer stem cells (CSCs) drive tumor recurrence and therapy resistance.
- OCT4 is crucial for CSC self-renewal and pluripotency.
Purpose of the Study:
- To evaluate melatonin's effect on breast cancer stem cell viability.
- To assess OCT4 expression in breast cancer stem cells after melatonin treatment.
Main Methods:
- Breast cancer stem cells (MCF-7, MDA-MB-231) were cultured as mammospheres.
- Cells were treated with melatonin.
- Cell viability was assessed using MTT assay.
- OCT4 expression was analyzed by immunocytochemistry.
Main Results:
- Melatonin treatment significantly decreased mammosphere cell viability.
- OCT4 expression was reduced in melatonin-treated cells compared to controls for both cell lines.
Conclusions:
- Melatonin demonstrates efficacy against breast cancer stem cells.
- Melatonin inhibits CSC viability, potentially through OCT4 downregulation.
- Melatonin shows potential as an alternative breast cancer therapy.
