Interaction of ICRF 159 with radiation, and its effect on sub-lethal and potentially lethal radiation damage in vitro.

ICRF 159 has been shown to increase the X-radiation sensitivity of exponentially growing EMT6 mouse tumour cells in vitro. This was found only with ICRF 159 exposure times longer than 10 h and only when the drug was given before irradiation. The increase in radiation sensitivity was expressed as a reduction of the shoulder of the radiation survival curve. As ICRF 159 was shown to have no effect on the repair of sub-lethal radiation damage, it was concluded that the drug reduced the capacity to accumulate such damage. ICRF 159 was also shown to have no effect on the repair of potentially lethal radiation damage in late plateau cells.