Tumor promotor TPA as a radioprotector against cell killing in C3H/10T 1/2 mouse embryo cells

In the course of studies examining the effects of TPA (12-0-tetradecanoyl-phorbol-13-acetate) on radiation induced transformation in mouse C3H/10T 1/2 cells it was noted that there was a consistent though small enhancement of cell survival after the single doses of radiation used. These studies were designed to examine the validity of this effect and to ascertain the mechanisms of action. Further, the earlier study showed that TPA (1 concentration) had little positive influence on sister chromatid exchange induction. Since the promotional activity of TPA had been proposed to act via enhanced somatic recombination as shown by increased SCE's it was considered desirable to assess the effects of additional concentrations of TPA