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Updated: May 28, 2025
Studying Triple Negative Breast Cancer Using Orthotopic Breast Cancer Model
Published on: March 20, 2020
Monensin Inhibits Triple-Negative Breast Cancer in Mice by a Na+-Dependent Cytotoxic Action Unrelated to Cytostatic
Simone Fiorilla1, Francesco Tasso1, Nausicaa Clemente1
1Department of Health Science, Università del Piemonte Orientale, Via Solaroli, 17, 28100 Novara, Italy.
Abstract:
Triple-negative breast cancer (TNBC) represents the most aggressive breast cancer subtype, defined by its limited therapeutic options and poor outcomes. This study investigated the therapeutic potential of targeting Na+ homeostasis in TNBC cells to induce TNBC inhibition. For this purpose, BALB/c mice were inoculated with 4T1-Luc2 breast cancer cells and treated with the Na+ ionophore monensin (8 mg/kg) or vehicle alone. Tumor development and cellular Na+ content were assessed using vivo live imaging techniques, while intracellular Na+ variations and cytotoxicity were evaluated through live cell analysis. Monensin treatment increased Na+ levels in cancerous tissues and reduced TNBC mass (monensin: 0.146 ± 0.06; vehicle: 0.468 ± 0.2 cm3; p < 0.001). This treatment induced extensive necrosis in TNBC tumors while preserving the structural and functional integrity of healthy organs and maintaining the proliferative activity of both tumor and normal tissues. Monensin did not alter the expression of proliferating nuclear antigen (PCNA) in 4T1-Luc2 cells but triggered cytotoxicity preceded by intracellular Na+ accumulation. Na+-free conditions prevented both Na+ accumulation and 4T1-Luc2 cell death. Thus, monensin exerts its antitumor effects in TNBC through a Na+-dependent and tumor-specific cytotoxic mechanism, without inducing cytostatic effects on normal or transformed tissues. Collectively, these findings underscore the potential of Na+ ionophores as promising therapeutic agents for TNBC.
Insights
Monensin, a Na+ ionophore, effectively inhibits triple-negative breast cancer (TNBC) growth by targeting sodium homeostasis. This targeted approach induces cancer cell death while preserving healthy tissues, offering a promising new therapeutic strategy for TNBC.
Area of Science:
- Oncology
- Cellular Biology
- Pharmacology
Background:
- Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and poor prognosis.
- Targeting cellular ion homeostasis presents a novel therapeutic strategy for TNBC.
- Understanding Na+ homeostasis is crucial for developing effective TNBC treatments.
Purpose of the Study:
- To investigate the therapeutic potential of targeting Na+ homeostasis in TNBC cells.
- To evaluate the efficacy of the Na+ ionophore monensin in inhibiting TNBC growth.
- To elucidate the mechanism of monensin's antitumor effects in TNBC.
Main Methods:
- In vivo studies using BALB/c mice inoculated with 4T1-Luc2 breast cancer cells.
- Treatment with monensin (Na+ ionophore) or vehicle control.
- In vivo live imaging for tumor development and Na+ content assessment.
- Live cell analysis for intracellular Na+ variations and cytotoxicity.
- Assessment of proliferating nuclear antigen (PCNA) expression.
Main Results:
- Monensin treatment significantly reduced TNBC tumor mass compared to vehicle control (0.146 vs. 0.468 cm³).
- Monensin induced extensive necrosis in TNBC tumors, preserving healthy organ integrity.
- Cytotoxicity was preceded by intracellular Na+ accumulation, dependent on extracellular Na+.
- Monensin did not alter PCNA expression, indicating a cytotoxic rather than cytostatic effect.
Conclusions:
- Monensin exerts potent antitumor effects in TNBC through a Na+-dependent, tumor-specific cytotoxic mechanism.
- Targeting Na+ homeostasis with ionophores like monensin is a promising therapeutic strategy for TNBC.
- Monensin demonstrates efficacy without inducing cytostatic effects on normal or transformed tissues.
