Amifostine protection against induced DNA damage in gamma-irradiated Escherichia coli cells depend on recN DNA repair gene product activity.

Amifostine is the most effective radioprotector known and the only one accepted for clinical use in cancer radiotherapy. In this work, the antigenotoxic effect of amifostine against gamma-rays was studied in Escherichia coli cells deficient in DNA damage repair activities. Assays of irradiated cells treated with amifostine showed that the drug reduced the genotoxicity induced by radiation in E. coli wild-type genotypes and in uvr, recF, recB, recB-recC-recF mutant strains, but not in recN defective cells. Thus, the mechanism of DNA protection by amifostine against gamma-radiation-induced genotoxicity appears to involve participation of the RecN protein that facilitates repair of DNA double-strand breaks. The results are discussed in relation to amifostine's chemopreventive potential.