High Mitochondrial DNA Content as a Key Determinant of Stemness, Proliferation, Cell Migration, and Cancer Metastasis In Vivo

Abstract

This study investigates the role of mitochondrial DNA (mtDNA) content in promoting aggressive cancer phenotypes. Utilizing breast cancer cell lines MCF7 and MDA-MB-231, researchers isolated subpopulations with high and low mtDNA content using SYBR Gold staining and flow cytometry. High mtDNA content correlated with increased mitochondrial function, stemness markers, proliferation rates, drug resistance, and metastatic potential. Treatment with Alovudine, an mtDNA synthesis inhibitor, significantly reduced metastasis in vivo without notably affecting primary tumor growth, highlighting mtDNA content as a potential therapeutic target.

Key Findings

• High mtDNA content in MCF7 and MDA-MB-231 cells is associated with enhanced mitochondrial mass, membrane potential, and ATP production.
• mtDNA-high cells exhibit increased stemness features, including higher CD44 expression and anchorage-independent growth.
• These cells demonstrate greater resistance to chemotherapeutic agents like Gemcitabine and Tamoxifen.
• In MDA-MB-231 cells, high mtDNA content leads to increased migration and invasion capabilities, suggesting a role in metastasis.
• Alovudine treatment effectively depletes mtDNA, shifting metabolism from oxidative phosphorylation to glycolysis, reducing metastasis by approximately 70% in vivo.

Methodology

Researchers employed SYBR Gold staining to differentiate between mtDNA-high and mtDNA-low subpopulations in breast cancer cell lines. Flow cytometry facilitated the isolation of these subpopulations, which were then subjected to various assays to assess mitochondrial function, stemness, proliferation, and drug resistance. Additionally, the effects of Alovudine on mtDNA content and metastatic potential were evaluated both in vitro and in vivo using the chorioallantoic membrane (CAM) assay.

Conclusion

The study underscores the significance of mtDNA content in regulating cancer cell behavior. High mtDNA levels enhance stemness, proliferation, and metastatic potential, while mtDNA depletion via Alovudine impairs these aggressive traits. Targeting mtDNA synthesis presents a promising strategy for mitigating metastasis without adversely affecting normal cell viability.