Retinoic acid inhibits the fixation of initial transformational damage in X-irradiated Balb/3T3 mouse fibroblasts in vitro.
We have examined the effects of all-trans retinoic acid (RA) on confluent holding recovery (cell survival) and on the fixation of initial transformational damage expressed as the ultimate yield of transformed foci following X-irradiation of density-inhibited cultures of Balb/3T3 cells. Non-cytotoxic concentrations of RA suppressed both recovery of potentially lethal damage and neoplastic transformation in a dose-dependent manner when added for 24 h during post-irradiation confluent holding after a dose of 5 Gy. At 100 microM, RA inhibited the fixation of initial transformational damage by 80%. These findings are discussed in terms of the hypothesis that retinoids may allow a selective enhancement of the inactivation of certain irradiated tumor cells in vivo while reducing the risk of secondary malignancies in successfully treated patients.
Rutz
H P
HP
Harvard School of Public Health, Department of Cancer Biology, Boston, MA 02115.
Little
J B
JB
D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D051379:Mice; D008807:Mice, Inbred BALB C; D014212:Tretinoin / Q000494:pharmacology*; D014965:X-Rays
D014212:Tretinoin