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Adaptive response and its variation in human normal and tumour cells
1Ottawa Regional Cancer Centre, Ontario, Canada. graaphorst@cancercare.on.ca
International Journal of Radiation Biology
|February 7, 2001
Summary
Human cells exhibit variable adaptive responses to radiation, observed in some cell lines but not others. This adaptive response (AR) is not linked to radiosensitivity or cell type.
Area of Science:
- Cellular and Molecular Biology
- Radiation Oncology
- Genetics and Genomics
Background:
- Mammalian cells display considerable variability in their adaptive responses.
- Understanding adaptive responses is crucial for predicting cellular behavior under radiation stress.
Purpose of the Study:
- To investigate the variability of adaptive responses in human cell lines.
- To determine if adaptive response correlates with radiosensitivity or cell origin (tumor vs. normal).
Main Methods:
- Six human cell lines (fibroblasts, melanoma, breast carcinoma) were cultured to plateau phase.
- Cells received varying inducing radiation doses (0-4.0 Gy) followed by challenge doses.
- Radiation response was assessed to identify adaptive response (AR).
Main Results:
- Adaptive response (AR) was observed in a subset of human cell lines.
- AR occurred within 2 hours, persisted up to 24 hours, and was dose-dependent (observed at 0.2-0.5 Gy, declining at higher doses).
- A radioresistant melanoma cell line showed sensitization, not AR, to all inducing doses.
Conclusions:
- Human cells are capable of demonstrating an adaptive response to radiation.
- The adaptive response is cell-line specific and not consistently related to radiosensitivity.
- No correlation was found between adaptive response and whether the cell line was derived from tumor or normal tissue.
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