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Energy and misonidazole toxicity: the effects of 5-thio-D-glucose
Abstract:
Cell inactivation and DNA damage (single-strand breaks) were used to study the effects of inhibitors of anaerobic glucose oxidation on the toxicity of misonidazole to hypoxic Chinese hamster cells. Citrate and 2-deoxyglucose produced no effects on the toxicity. 5-thio-D-glucose (5-TG) protected cells of the CH2B2 line to some extent (SSB decreased by about 30%). In the CHO lines used (wild, and ethylmethanesulfonate-sensitive mutants), 5-TG had varied effects. Non-protein sulfhydryl (NPSH) levels were measured in all lines. Cells with lower NPSH levels are more sensitive to misonidazole; these are the cells which are protected by 5-TG. Cell line variations must be considered when studying interactions between a drug and other forms of treatment as possible treatments of cancer.
Insights
5-thio-D-glucose partially protected Chinese hamster cells from misonidazole toxicity by reducing DNA damage. This protection was linked to non-protein sulfhydryl levels, highlighting cell line variations in cancer treatment research.
Area of Science:
- Cell biology
- Cancer research
- Radiosensitization
Background:
- Misonidazole is a hypoxic cell sensitizer used in cancer therapy.
- Understanding drug interactions is crucial for optimizing cancer treatment strategies.
- Hypoxic cells are resistant to radiation and chemotherapy.
Purpose of the Study:
- To investigate the effects of anaerobic glucose oxidation inhibitors on misonidazole toxicity.
- To determine if 5-thio-D-glucose (5-TG) can protect hypoxic cells from misonidazole-induced DNA damage.
- To explore the relationship between non-protein sulfhydryl (NPSH) levels and misonidazole sensitivity.
Main Methods:
- Chinese hamster cells (CH2B2, CHO wild-type, and mutants) were exposed to misonidazole.
- Inhibitors of anaerobic glucose oxidation, including 5-TG, citrate, and 2-deoxyglucose, were tested.
- Cell inactivation and single-strand DNA breaks (SSB) were measured.
- Non-protein sulfhydryl (NPSH) levels were quantified.
Main Results:
- Citrate and 2-deoxyglucose did not affect misonidazole toxicity.
- 5-TG provided partial protection to CH2B2 cells, reducing SSB by approximately 30%.
- 5-TG exhibited varied effects across different CHO cell lines.
- Lower NPSH levels correlated with increased misonidazole sensitivity and protection by 5-TG.
Conclusions:
- 5-thio-D-glucose can modulate misonidazole toxicity in hypoxic cells.
- Non-protein sulfhydryl levels are a key factor in misonidazole sensitivity and 5-TG's protective effect.
- Cell line-specific responses necessitate careful consideration when combining misonidazole with other agents for cancer treatment.