Low dose hypersensitivity in the T98G human glioblastoma cell line.
OBJECTIVE
To examine the low dose-response of a human radioresistant glioblastoma cell line (T98G) using two different methods to measure surviving fraction and to define the influence of cell cycle phase on this response.


METHODS
The survival of cells following exposure to single very low doses of X-rays in vitro was measured using either the Dynamic Microscopic Image Processing Scanner (DMIPS) or a Cell Sorter (CS). The DMIPS was also used to measure the low dose survival response of T98G cells following manipulation of their progression through the cell cycle.


RESULTS
With both methods, T98G demonstrated marked low dose hyper-radiosensitivity (HRS) and the two methods produced very similar data in the low dose region of the survival curve. However, the CS protocol produced less variable results and was the more efficient method of generating low dose data. HRS was also demonstrated when these cells were irradiated while held in reversible arrest in the G1 phase of the cell cycle, but the effect was less marked than in the asynchronous population.


CONCLUSIONS
T98G glioblastoma cells demonstrate marked HRS, which is a characteristic of the whole population rather than being due to the influence of a small subpopulation of hyper-radiosensitive cells within a particular phase of the cell cycle.
Short
S
S
Gray Laboratory Cancer Research Trust, Mount Vernon Hospital, Northwood, UK. short@graylab.ac.uk
Mayes
C
C
Woodcock
M
M
Johns
H
H
Joiner
M C
MC
D002453:Cell Cycle / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D016193:G1 Phase / Q000528:radiation effects; D005909:Glioblastoma / Q000532:radiotherapy*; D006801:Humans; D011836:Radiation Tolerance; D014407:Tumor Cells, Cultured