Simultaneous evaluation of radiation-induced apoptosis and micronuclei in five cell lines.

PURPOSE

This study was conducted to clarify the relationship among the frequencies of micronuclei (MN) and apoptosis, and clonogenic cell survival after irradiation.

MATERIALS AND METHODS

The frequencies of MN and apoptosis were compared in the surviving fraction in three human tumour cell lines and two rodent cell lines at various irradiation doses.

RESULTS

The SHIN-3, DU-145 and CHO-K1 cells showed dose-dependent increases of MN per binucleate cell and an excellent correlation between the MN frequency and surviving fraction after irradiation. The F9 and COLO 320DM cells did not show this correlation. The number of apoptotic cells increased according to the increase in radiation dose in the F9 and COLO 320DM cells, but not in the SHIN-3, DU-145 or CHO-K1 cells.

CONCLUSIONS

The detection of the MN frequency alone is insufficient to measure cellular intrinsic radiosensitivity. The simultaneous use of the MN assay and the detection of apoptotic cells would be more reliable as a method for predicting cell survival after radiation.