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Cytotoxicity of dual function nitrofurans in rodent and human tumor cells
1Tumor Biology Division, University of Rochester Cancer Center, NY 14642.
Abstract:
The efficacy and selective hypoxic cell cytotoxicity of four dual function nitrofurans and two nitroimidazole-aziridines was determined in human (A549, HT-29) and rodent (KHT/iv) tumor cells. All bioreductive compounds were found to be less effective at killing human than mouse tumor cells (approximately 2-6-fold). This reduced cytotoxicity in the human tumor cells occurred irrespective of the state of oxygenation. In addition, the degree of selective toxicity toward hypoxic cells or the cytotoxicity factor (CF), defined as the ratio of the surviving fraction in air to that under hypoxic conditions, was (a) greater for the nitroimidazole-aziridines than for the nitrofurans and (b) less in the human than the rodent tumor cell lines investigated. For example, CF values in A549 or HT-29 cells typically were 2-4-fold lower than those determined in KHT/iv cells. This reduction in the CF in the human cells resulted from a greater loss in the hypoxic toxicity than in the aerobic toxicity when compared with the rodent cells.
Insights
Nitrofurans and nitroimidazole-aziridines showed reduced efficacy against human tumor cells compared to rodent cells. Selective toxicity for hypoxic cells was also lower in human cell lines, impacting drug development for cancer therapy.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Hypoxic tumor cells are resistant to conventional therapies.
- Bioreductive drugs offer potential for selective cancer cell killing.
- Nitrofurans and nitroimidazole-aziridines are classes of bioreductive agents.
Purpose of the Study:
- To evaluate the efficacy and selective hypoxic cell cytotoxicity of nitrofurans and nitroimidazole-aziridines.
- To compare the activity of these compounds in human and rodent tumor cell lines.
- To understand the differential response of human versus rodent tumor cells to these agents.
Main Methods:
- Assessed cytotoxicity of nitrofurans and nitroimidazole-aziridines in human (A549, HT-29) and rodent (KHT/iv) tumor cells.
- Determined drug efficacy under both normoxic and hypoxic conditions.
- Calculated the cytotoxicity factor (CF) to quantify selective toxicity.
Main Results:
- All tested bioreductive compounds exhibited 2-6 fold lower cytotoxicity in human tumor cells compared to rodent tumor cells.
- Reduced cytotoxicity in human cells was observed regardless of oxygenation status.
- Nitroimidazole-aziridines demonstrated greater selective toxicity for hypoxic cells than nitrofurans.
- The cytotoxicity factor (CF) was significantly lower (2-4 fold) in human cell lines (A549, HT-29) than in rodent cell lines (KHT/iv).
- This reduction in CF for human cells was attributed to a more pronounced decrease in hypoxic toxicity relative to aerobic toxicity.
Conclusions:
- Human tumor cells display reduced sensitivity to bioreductive nitrofurans and nitroimidazole-aziridines compared to rodent counterparts.
- The selective toxicity of these agents towards hypoxic cells is diminished in human tumor cell lines.
- These findings highlight species-specific differences in drug response and necessitate further investigation for effective cancer therapeutic development.