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Mitochondrial DNA determines the cellular response to cancer therapeutic agents
Abstract:
Mutations in the mitochondrial genome leading to mitochondrial dysfunction have been reported in a variety of cancers. However, the potential implication of these findings in the cellular response to cancer therapeutic agents is unclear. To examine the importance of mitochondrial DNA (mitDNA) encoded functions in cancer therapeutic response, we determined the clonogenic survival of HSL2 (Rho+, HeLa subline), and its derivative cell line lacking mitDNA (Rho0) after exposure to different anticancer agents. We found that isogenic Rho0 cells lacking mitDNA were extremely resistant to adriamycin and photodynamic therapy (PDT) induced cell death, whereas the Rho+ cell line was sensitive. However, there was no measurable difference in the responses of these cell lines to either alkylating agent or gamma-radiation. We show that the development of resistance to adriamycin was not due to changes in apoptotic cell death, cell cycle response or to the uptake of adriamycin in isogenic Rho0 cells. We also demonstrate that exposure of HeLa cells to adriamycin leads to mutations in mitDNA. These studies provide direct evidence that mitDNA plays an important role in cellular sensitivity to cancer therapeutic agents.
Insights
Mitochondrial DNA (mitDNA) is crucial for cancer drug response. Cells lacking mitDNA show resistance to adriamycin and photodynamic therapy, indicating mitDNA
Area of Science:
- Cancer Biology
- Mitochondrial Biology
- Pharmacology
Background:
- Mitochondrial dysfunction and mutations in mitochondrial DNA (mitDNA) are observed in various cancers.
- The role of mitDNA-encoded functions in cancer therapeutic response remains largely unknown.
Purpose of the Study:
- To investigate the significance of mitDNA-encoded functions in cellular sensitivity to anticancer agents.
- To determine if mitDNA integrity influences the efficacy of chemotherapy and other cancer therapies.
Main Methods:
- Comparison of clonogenic survival between a human cervical cancer cell line (HeLa, Rho+) and its mitDNA-depleted derivative (Rho0) after exposure to various anticancer agents.
- Assessment of adriamycin uptake, apoptotic cell death, and cell cycle response in Rho+ and Rho0 cells.
- Analysis of mitDNA mutations following adriamycin treatment.
Main Results:
- Rho0 cells lacking mitDNA exhibited extreme resistance to adriamycin and photodynamic therapy (PDT).
- No significant difference in response was observed between Rho+ and Rho0 cells when treated with alkylating agents or gamma radiation.
- Adriamycin resistance in Rho0 cells was not attributed to altered apoptosis, cell cycle, or drug uptake.
- Adriamycin treatment induced mutations in the mitDNA of HeLa cells.
Conclusions:
- Mitochondrial DNA plays a critical role in cellular sensitivity to specific cancer therapeutic agents like adriamycin and PDT.
- Targeting or preserving mitDNA function could be a strategy to modulate cancer treatment efficacy.